Past Paper Qs Electric Current-1

– 8 –

M00/430/H(2)

SECTION B

This section consists consists of four questions: questions: B1, B1, B2, B3 and B4. Answer any B1.

two questions

This question is in two parts. Part 1 is about electrical circuits and about the Carnot Cycle and Entropy. Part 1.

(a)

in this section.

Part 2 (the

shorter part) is

Electrical circuits

You are are given given the apparatus apparatus shown shown below below which which is also also identifie identified d by the the approp appropriate riate circuit circuit symbol. The 12 V battery has negligible internal resistance.

A

V

ammeter

voltmeter

bulb

battery (12 V)

variable resistor

Draw a circuit diagram showing how this apparatus should be connected so that the current through the bulb can be measured as the potential difference across the bulb is varied from zero to 12 V.

[4]

(This question continues on the following page)

220-227

– 9 –

M00/430/H(2)

(Question B1 Part 1 continued)

(b)

The grap graph h below below shows shows the the relat relation ionsh ship ip betwe between en the the curren currentt I through through a particular filament lamp and the potential difference V across across it.

14 12 10 V / V

8 6 4 2 0 0.00

0.05

0.10

0.15

0.20

0.25

/ A I / (i)

State State whet whether her or not not the the filamen filamentt of the lamp lamp obey obeyss Ohm’s Ohm’s law. law.

[1]

..................................................................... (ii)

What is is the resista resistance nce of of the lamp lamp when when the potent potential ial differen difference ce across across it it is very very small? small?

[2]

..................................................................... ..................................................................... (iii) How much much power power is dissipat dissipated ed in the lamp lamp when when the potentia potentiall difference difference across across it is 12 V?

[2]

..................................................................... .....................................................................

(This question continues on the following page) 220-227

Turn over

– 9 –

M00/430/H(2)


(b)

The grap graph h below below shows shows the the relat relation ionsh ship ip betwe between en the the curren currentt I through through a particular filament lamp and the potential difference V across across it.

14 12 10 V / V

8 6 4 2 0 0.00

0.05

0.10

0.15

0.20

0.25

/ A I / (i)

State State whet whether her or not not the the filamen filamentt of the lamp lamp obey obeyss Ohm’s Ohm’s law. law.

[1]

..................................................................... (ii)

What is is the resista resistance nce of of the lamp lamp when when the potent potential ial differen difference ce across across it it is very very small? small?

[2]

..................................................................... ..................................................................... (iii) How much much power power is dissipat dissipated ed in the lamp lamp when when the potentia potentiall difference difference across across it is 12 V?

[2]

..................................................................... .....................................................................


Turn over

– 10 –

M00/430/H(2)


(c)

A student student conne connects cts a filament filament lamp lamp to a dry dry batter battery y via via a switch. switch. A high high resista resistance nce voltmeter voltmeter connected across the battery reads 12 V when the switch is open. When the switch is closed the voltmeter reads 10.8 V. (i)

Sugge ggest wh why th this mig might be. be.

[2]

..................................................................... ..................................................................... ..................................................................... (ii)

On measu measuring ring the curre current nt throug through h the lamp the student student finds finds it to be 0.18 0.18 A. A. Calculate Calculate the internal resistance of the battery.

[3]

..................................................................... ..................................................................... .....................................................................


– 8 –

N00/430/H(2)

A3. Electric circuit This question involves physical reasoning and calculations for electric circuits. Light bulbs are marked with the rating 10 V; 3 W. Suppose you connect three of the bulbs in series with a switch and a 30 V battery as shown in Figure 1 below. Switch S is initially open. S 30 V

A

B

C

Figure 1 (a) (a)

A stu stude dent nt tel tells ls you that that aft after er switc switch h S is closed, bulb C will light up first, because electrons from the negative terminal of the battery will reach it first, and then go on to light bulbs B and A in succession. Is this prediction and reasoning correct? How would you reply?

[2]

......................................................................... ......................................................................... ......................................................................... ......................................................................... ......................................................................... (b)

State how the the brightnes brightnesses ses of of the three three bulbs bulbs in in the circui circuitt will compar comparee with each each other. other.

[1]

......................................................................... .........................................................................


880-227

– 9 –

N00/430/H(2)

(Question A3 continued)

(c) (c)

2 below. The The stud studen entt now now conn connec ects ts a four fourth th bul bulb b D across bulb B as shown in Figure 2 below. S 30 V

A

B

C

D

Figure 2 When she connects D, what will happen to the brightnesses of bulbs A, B and C? Explain your reasoning.

[3]

......................................................................... ......................................................................... ......................................................................... ......................................................................... ......................................................................... ......................................................................... (d)

Assuming Assuming that the the resistan resistance ce of the bulbs bulbs remains remains consta constant, nt, calcula calculate te the power power output output of bulb B: (i) (i)

[1]

1; in the the or origin iginaal cir circcuit uit in in Figure 1; .....................................................................

(ii) (ii)

2. in the the mod modif ifie ied d cir circu cuit it in in Figure 2.

[3]

..................................................................... ..................................................................... ..................................................................... .....................................................................

880-227

Turn over

J B J

K>AL?@>LMGBH

!"#$%&' )

!"#$%$"&'( *+(& "#(,')*+

!"" .+'(&%/#(

%# &0' (1"2'( 1-/3%$'$4

!"#$ &'($)#*+ #$ ,-*') .*/(0 1#$$#.,)#*+ #+ , 0($#$)*0 ,+1 )"( #+)(0+,2 0($#$),+3( *4 , -,))(056 7+ )"( 3#03'#) -(2*/ )"( 8,0#,-2( 0($#$)*0 3,+ -( ,19'$)(1 )* ",8( :+*/+ 8,2'($ *4 0($#$),+3( 56 !"( -,))(05 ",$ ,+ '+:+*/+ #+)(0+,2 0($#$),+3( - 6 - ! ! ! !

6

; 5

!"( ),-2( -(2*/ $"*/$ )"( 0(3*01(1 8,2'( 6 *4 )"( 3'00(+) #+ )"( 3#03'#) 4*0 1#44(0(+) 8,2'($ *4 56 !"( 2,$) 3*2'<+ =#8($ )"( 3,23'2,)(1 8,2'( *4 )"( .*/(0 7 1#$$#.,)(1 #+ )"( 0($#$)*06 ' %

& % ) !>6>A

> A6> B6> @6> ?6> E6> D6> A>6> G,H

A6C> A6B> A6>> >6DE >6FC >6E> >6C> >6?@

# % ,

; > A6? B6> B6B B6@ B6B B6>

I*<.2()( )"( 2,$) 2#+( *4 )"( ),-2( -5 3,23'2,)#+= )"( .*/(0 1#$$#.,)(1 #+ )"( 8,0#,-2( 0($#$)*0 /"(+ #)$ 8,2'( #$ A>6> !6

89:

6666666666666666666666666666666666666666666666666666666666666666666666666 6666666666666666666666666666666666666666666666666666666666666666666666666 6666666666666666666666666666666666666666666666666666666666666666666666666

;<0%( .+'(&%/# 2/#&%#+'( /# &0' =/>>/,%#? 1"?'@

DDANAFA

J K J

L65MEK6MN!O#

!"#$%&'() +, -()&')#$./ !"#

$% '()* +(,-' .% 3 /0 12.32 4. 3*'2 3 < 56=6 !=

!56

7 8'4'9:/2' 4*' !"#$%&'( -2)'94(/24; /2 4*' +(,-' .% 4 012

========================================================================= ========================================================================= ========================================================================= !)#

>2 4*' ?9/8 "',.3 @,.4 ( ?9(@* .% @.3'9 4 (?(/204 9'0/04(2)' 3= )*$ ,$' -,.%&/( (00$0 "!0#1 =

052

!8#

$4 )(2 "' 0*.32 4*(4 4*' @.3'9 8/00/@(4'8 /2 4*' 'A4'92(, 9'0/04.9 /0 ( :(A/:-: 3*'2 4*' +(,-' .% /40 9'0/04(2)' 3 /0 'B-(, 4. 4*' +(,-' .% 4*' /24'92(, 9'0/04(2)' 6 .% 4*' "(44'9; '7$7 3 < 6 = C0' 4*/0 /2%.9:(4/.2 (28 ;.-9 ?9(@* 4. %/28 4*' +(,-' .% 6 =

0,2

========================================================================= !'#

D*' :(2-%()4-9'9 .% 4*' "(44'9; ?/+'0 4*' +(,-' .% /40 /24'92(, 9'0/04(2)' (0 E=F6 ! ! 6=65 != $0 4*' +(,-' .% 6 4*(4 ;.- ."4(/2'8 %9.: ;.-9 ?9(@* ).20/04'24 3/4* 4*' :(2-%()4-9'9G0 +(,-'H IA@,(/2=

082

========================================================================= ========================================================================= ========================================================================= ========================================================================= PP5Q5R5

2&0, $3(0

K D K

L;4MDN;MOA4BP

!"# $%&'()*+ &(-.% /%0+& 12//*3

! #$%&'()* %'+,$ %*-.,%*/ ' #$&*0&,') +,11*%*02* $1 34 5 &$ $#*%'&*6 78* $0)9 /.##)9 ':',)'()* ,/ ' 4; 5 /.##)96 <0 $%+*% &$ ./* &8* %'+,$ =,&8 &8,/ /.##)9> ' /&.+*0& ,02).+*/ ' /*%,*/ %*/,/&$%> ?> '/ /8$=0 ,0 &8* 2,%2.,& (*)$=6 4; 5 @@@@

?

A'B

?'+,$

78* %'+,$ ,/ +*/,C0*+ &$ +%'= ' 2.%%*0& $1 ;6D ! =,&8 34 5 '2%$// ,&6 78* ,0&*%0') %*/,/&'02* $1 &8* 4; 5 /.##)9 ,/ /E'))6 F')2.)'&* &8* :').* $1 &8* %*/,/&$%> ?> %*-.,%*+ 1$% &8* %'+,$ &$ $#*%'&* 0$%E'))9> =8*0 2$00*2&*+ ,0 &8* 2,%2.,& '($:*6

!"#

6666666666666666666666666666666666666666666666666666666666666666666666666 6666666666666666666666666666666666666666666666666666666666666666666666666 6666666666666666666666666666666666666666666666666666666666666666666666666 A(B

78%** %*/,/&$%/ '%* ':',)'()* =,&8 E'G,E.E #$=*% %'&,0C/ 4 H> I H '0+ 3; H %*/#*2&,:*)96 JG#)',0 =8,28 %4+ $1 &8*/* %*/,/&$%/ &8* /&.+*0& /8$.)+ 28$$/* 1$% &8* 2,%2.,&6

!$#

6666666666666666666666666666666666666666666666666666666666666666666666666 6666666666666666666666666666666666666666666666666666666666666666666666666 6666666666666666666666666666666666666666666666666666666666666666666666666 A2B

JG#)',0 =8'& =$.)+ 8'##*0 ,1 ' %*/,/&$% =,&8 ' )$=*% #$=*% %'&,0C &8'0 &8'& %*-.,%*+ ,/ 28$/*06

!%#

6666666666666666666666666666666666666666666666666666666666666666666666666 6666666666666666666666666666666666666666666666666666666666666666666666666 6666666666666666666666666666666666666666666666666666666666666666666666666

&'()* ,-.*/)01 201/)1-.* 01 /(. 304405)16 786.9

QQ4@3R3

D E D

F=
!"#$%&'() +, -()&')#$./ !"#

$% '()*+%'),-* .,+./,) 01+ 2+1"/.,%3 )4* +*5/,+*" 61+7,%3 -1()'3* 01+ )4* +'",1 ,8 8416% 9*(16:

0<

<= >

0B

;'",1

?4* +*8,8)'%.*8 0B '%" 0< '+* -*+@ A/.4 (*88 )4'% )4* +*8,8)'%.* 10 )4* +'",1: C'(./(')* )4* +'),1 10 0B )1 0< ,% 1+"*+ 01+ )4* 12*+'),%3 -1()'3* 10 )4* +'",1 )1 9* *5/'( )1 B< >:

123

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

LL
!"#$ &'(#

E /F E

GHIJKIHJL?0@

!"#$%&'() +, -()&')#$./ !"#$ &

!"#$%&'$(" *&+*#&%'#, +- %.+ /0 1 -'"(2#3% "(2*,

43 +&5#& %+ 2#(,6&# %7# 8+"%(9#:$6&% !012/ $7(&($%#&',%'$, +- ( "(2*; ( ,%65#3% ,#%, 6* %7# -+""+.'39 #"#$%&'$(" $'&$6'%< /0 1 =(%%#&> - - - -

?(@

A3 %7# $'&$6'% (=+8#; (55 $'&$6'% ,>2=+", ,7+.'39 %7# $+&&#$% *+,'%'+3, +- (3 '5#(" (22#%#& "'( (3 '5#(" 8+"%2#%#& %7(% .+6"5 (""+. %7# 012 $7(&($%#&',%'$, +- %7', "(2* %+ =# 2#(,6<

3,4

B7# 8+"%2#%#& (35 %7# (22#%#& (&# $+33#$%#5 $+&&#$%"> '3 %7# $'&$6'% (=+8#< ?=@

!C*"('3 .7> %7# *+%#3%'(" 5'--#$# ($&+,, %7# "(2* ?'@

$(33+% =# '3$&#(,#5 %+ /0 1<

3,4

<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< ?''@

$(33+% =# 8$#5 %+ D#&+<

3,4

<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

!56'% 7#$%&'() -()&')#$% () &6$ 8(99(:'); <=;$/

MMI:/N/

? @A ?

BCDEFDCEG4H5

!"#$%&'() +, -./& , 0()&')#$12 !" $%&'("$&)*' +)(+,)& -.( /'$0,()"1 &2' 345 +2$($+&'()0&)+ ,0'0 $ -(&$)&'.6 1'7'1$/ 3 4+5

4)5

4))5

6($7 $ +)(+,)& &2$& ,0'0 $ 8.&'"&)$% 9)*)9'( &. '"$:%' &2' 345 +2$($+&'()0&)+0 .- &2' -)%$/'"& &. :' -.,"93

89:

;<8%$)" 72= &2)0 +)(+,)& '"$:%'0 &2' 8.&'"&)$% 9)--'('"+' $+(.00 &2' %$/8 &. :' ('9,+'9 &. >'(. *.%&03

8,:

333333333333333333333333333333333333333333333333333333333333333333333 333333333333333333333333333333333333333333333333333333333333333333333

!;<'% =#$%&'() 0()&')#$% () &<$ >(66(?')@ -.@$2

IIDJ@A@

!"#$ &'(#

C 2D C

E=F;GF=;H?3@

!"#$%&'() +, -./& , 0()&')#$12 !"# %&'(" )#*+, -"+,- ."# 345 /"'&'/.#&0-.0/ 1+& .,+ 23 4 10*'5#6. *'5(- 7 '68 9: (+.#6.0'* 8011#/# ;4

*'5( 7

*'5( 9

23

= =

=:>

2:= /<&. ; 7

?8@

A.'.# '68 #B(*'06 ,"0/" *'5( "'- ."# %&#'.#& (+,#& 80--0('.0+6 1+& ' (+.#6.0'* 8011#/# +1 23 4:

678

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

!9:'% ;#$%&'() 0()&')#$% () &:$ <(==(>')? -.?$2

DDFI2J2

A 2B A

CDEFGEDFH:3;

!"#$%&'() +, -./& , 0()&')#$12 !"# %&' ()*+, )-# .'& /'..#/%#0 1. ,#-1#, &1%" ) 23 4 5)%%#-6 ), ,"'&. 5#('&7 23 4 5)%%#-6 - - - -

()*+ 8 :#;

:1;

()*+ 9 345

<%)%# "'& %"# /=--#.% 1. ()*+ 8 /'*+)-#, &1%" %")% 1. ()*+ 97 777777777777777777777777777777777777777777777777777777777777777777777 777777777777777777777777777777777777777777777777777777777777777777777

:11;

>,# %"# 789 /")-)/%#-1,%1/, '? %"# ()*+, %' 0#0=/# %"# %'%)( /=--#.% ?-'* %"# 5)%%#-67

365

777777777777777777777777777777777777777777777777777777777777777777777 777777777777777777777777777777777777777777777777777777777777777777777 777777777777777777777777777777777777777777777777777777777777777777777 777777777777777777777777777777777777777777777777777777777777777777777 3,5

:111; @'*+)-# %"# +'&#- 01,,1+)%#0 56 %"# %&' ()*+,7 777777777777777777777777777777777777777777777777777777777777777777777 777777777777777777777777777777777777777777777777777777777777777777777

IIEJ2K2

!"#$ &'(#

I ? I

JAKLK>@LM-F/

!"#$%&'() +, -()&')#$./ !"##$%& $($)&#*)*&+

! #$%% &' $%$#()&*&(+,$ '&)#$ -$.*.'./ 0 012 +1($)10% )$3+3(01#$ 1 +3 #&11$#($2 +1 3$)+$3 4+(5 0 )$3+3(&) 67 03 35&41 8$%&4.

0

1

6

> > 95$ #$%% 3:;;%+$3 ?.@!@A B &' $1$)<= 45$1 C.? !@A D &' #50)<$ *&,$3 #&*;%$($%= )&:12 (5$ #+)#:+(. 95$ #:))$1( +1 (5$ #+)#:+( +3 #&13(01(.

-#/

-+/

D0%#:%0($ (5$ $.*.'. 0 &' (5$ #$%%.

234

..................................................................... ..................................................................... ..................................................................... -++/

95$ )$3+3(&) 6 503 )$3+3(01#$ E.A !. 95$ ;&($1(+0% 2+''$)$1#$ 8$(4$$1 +(3 ($)*+10%3 +3 @.F G. H$($)*+1$ (5$ +1($)10% )$3+3(01#$ 1 &' (5$ #$%%.

254

..................................................................... ..................................................................... ..................................................................... ..................................................................... -+++/ D0%#:%0($ (5$ (&(0% $1$)<= ()013'$) +1 (5$ )$3+3(&) 6.

234

..................................................................... ..................................................................... .....................................................................

!67'% 8#$%&'() -()&')#$% () &7$ 9(::(;')< =><$/

FFKN@OO

> ? >

@ABCBDECF!G$

!"#$%&'() +, -()&')#$./ !"#$ &'()*"+', "- .'*/( 01 2 ("/34' /05'4 01 '4').*")24 )0-56)."0-, .7' /')72-"(/ +8 97")7 .7' '-'*:8 .*2-(1'* "- .7' *'("(.0* ; .2<'( 342)'=

012

===================================================================== ===================================================================== ===================================================================== ===================================================================== ===================================================================== =====================================================================

!34'% 5#$%&'() -()&')#$% () &4$ 6(77(8')9 :;9$/

GGBHEII

!"#$ &'(#

– 19 – B2.

This question is in satellite. Part 1

two parts. Part 1 is

N04/4/PHYSI/HP2/ENG/TZ0/XX+

about electric circuits and

Part 2 is

about an orbiting

Electric circuits

Susan sets up the circuit below in order to measure the current-voltage ( I-V ) characteristic of a small filament lamp.

The supply is a battery that has an e.m.f. of 3.0 V and the ammeter and voltmeter are considered to be ideal. The lamp is labelled by the manufacturer as “3 Volts, 0.6 Watts”. (a)

(i)

Explain what information this labelling provides about the normal operation of the lamp.

[2]

................................................................. ................................................................. ................................................................. ................................................................. ................................................................. (ii)

Calculate the current in the filament of the lamp when it is operating at normal brightness.

[2]

................................................................. ................................................................. ................................................................. ................................................................. ................................................................. (This question continues on the following page) 8804-6502

Turn over

– 20 –


(Question B2, part 1 continued) Susan sets the variable resistor to its maximum value of resistance. She then closes the switch S and records the following readings. Ammeter reading = 0.18 A

Voltmeter reading = 0.60 V

She then sets the variable resistor to its zero value of resistance and records the following readings. Ammeter reading = 0.20 A (b)

(i)

Voltmeter reading = 2.6 V

Explain why, by changing the value of the resistance of the variable resistance, the potential difference across the lamp cannot be reduced to zero or be increased to 3.0 V.

[2]

................................................................. ................................................................. ................................................................. ................................................................. (ii)

Determine the internal resistance of the battery.

[3]

................................................................. ................................................................. ................................................................. .................................................................


8804-6502

– 21 –


(Question B2, part 1 continued) (c)

Calculate the resistance of the filament when the reading on the voltmeter is (i)

0.60 V.

[1]

................................................................. ................................................................. (ii)

2.6 V.

[1]

................................................................. ................................................................. (d)

Explain why there is a difference between your answers to (c) (i) and (c) (ii).

[2]

. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... . . .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... . . .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... . (e)

Using the axes below, draw a sketch-graph of the I-V characteristic of the filament of the lamp. ( Note: this is a sketch-graph; you do not need to add any values to the axis.)

[1]

I

0 0

V


8804-6502

Turn over

– 22 –


(Question B2, part 1 continued) The diagram below shows an alternative circuit for varying the potential difference across the lamp.

The potential divider XZ has a potential of 3.0 V across it. When the contact is at the position Y, the resistance of XY equals the resistance of YZ which equals 12 !. The resistance of the lamp is 4.0 !. (f)

Calculate the potential difference across the lamp.

[4]

. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... . . .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... . . .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... . . .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... . . .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .

(Question B2 continues on page 24)

8804-6502

– 23 – B3.

M05/4/PHYSI/HP2/ENG/TZ1/XX+

This question is in two parts. Part 1 is about e.m.f. and internal resistance. wave properties of light and electrons. Part 1

Part 2 is

about the

e.m.f. and internal resistance

A dry cell has an e.m.f. E and internal resistance r and is connected to an external circuit. There is a current I in the circuit when the potential difference across the terminals of the cell is V . V

r I

(a)

E

State expressions, in terms of E , V , r and I where appropriate, for (i)

the total power supplied by the cell.

[1]

................................................................. (ii)

the power dissipated in the cell.

[1]

................................................................. (iii) the power dissipated in the external circuit.

[1]

................................................................. (b)

Use your answers to (a) to derive a relationship between V , E , I and r .

[2]

. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... . . .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... . . .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .


Turn over

2205-6508 

– 24 –


(Question B3, part 1 continued) The graph below shows the variation of V with I for the dry cell.

1.6 1.5 1.4 1.3 1.2 1.1 1.0 0.90

V/V

0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.0 0.0

0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.0

1.1

1.2

1.3

I / A


2205-6508 

– 25 –



(d)

Complete the diagram below to show the circuit that could be used to obtain the data from which the graph was plotted.

[3]

Use the graph, explaining your answers, to (i)

determine the e.m.f. E of the cell.

[2]

................................................................. ................................................................. (ii)

determine the current in the external circuit when the resistance R of the external circuit is very small.

[2]

................................................................. ................................................................. ................................................................. ................................................................. [3]

(iii) deduce that the internal resistance r of the cell is about 1.2  . ................................................................. ................................................................. ................................................................. ................................................................. .................................................................

(This question continues on the following page) Turn over

2205-6508 

– 26 –


(Question B3, part 1 continued) (e)

The maximum power dissipated in the external circuit occurs when the resistance of the external circuit has the same value as the internal resistance of the cell. Calculate the maximum power dissipation in the external circuit.

[3]

. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... . . .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... . . .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... . . .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .. .. .. .. .. ... .. .. .. .. ... .

(This question continues on page 28)

2205-6508 

– 21 – B3.


This question is in three parts. Part 1 is about electrical components. forces and Part 3 is about electromagnetic induction. Part 1

(a)

Part 2 is about magnetic

Electrical components

In the space below, draw a circuit diagram that could be used to determine the current-voltage (I-V) characteristics of an electrical component X.

[2]

component X


Turn over

2205-6514 

– 22 –


(Question B3, part 1 continued) The graph below shows the I-V characteristics for the component X. I / A 6

4

2

0 –8

–6

–4

–2

0

2

4

6

8 V /V

–2

–4

–6 The component X is now connected across the terminals of a battery of e.m.f. 6.0 V and negligible internal resistance. (b)

Use the graph to determine (i)

the current in component X.

[1]

................................................................. (ii)

the resistance of component X.

[2]

................................................................. ................................................................. .................................................................


2205-6514 

– 23 –


(Question B3, part 1 continued) A resistor R of constant resistance 2.0  is now connected in series with component X as shown below. X

R 2.0 

E (c)

(i)

On the graph opposite, draw the I-V characteristics for the resistor R.

[2]

(ii)

Determine the total potential difference E that must be applied across component X and across resistor R such that the current through X and R is 3.0 A.

[2]

................................................................. ................................................................. .................................................................


Turn over

2205-6514 

– 14 –


(Question B1 continued) Part 2

Heating water electrically

The diagram below shows part of the heating circuit of a domestic shower. insulated wire water pipe 240 V supply





cold water 14 C

hot water 40 C insulated heating element

Cold water enters the shower unit and flows over an insulated heating element. The heating element is rated at 7.2 kW, 240 V. The water enters at a temperature of 14 C and leaves at a temperature of 40 C. The specific heat capacity of water is 4.2 % 103 J kg!1 K !1. 



(a)

Describe how thermal energy is transferred from the heating element to the water.

[3]

........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. ....... (b)

Estimate the flow rate in kg s!1 of the water.

[4]

........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. .......


2206-6508 1436

– 15 –



Suggest two reasons why your answer to (b) is only an estimate. 1.

[2]

............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. .

2.

............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. .

(d)

Calculate the current in the heating element when the element is operating at 7.2 kW.

[2]

........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. ....... (e)

Explain why, when the shower unit is switched on, the initial current in the heating element is greater than the current calculated in (d).

[2]

........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. .......


Turn over

2206-6508 1536

– 16 –


(Question B1, part 2 continued) (f)

In some countries, shower units are operated from a 110 V supply. A heating element operating with a 240 V supply has resistance R240 and an element operating from a 110 V supply has resistance R110. (i)

Deduce, that for heating elements to have identical power outputs R110 R240



0.21.

[3]

.................................................................. .................................................................. .................................................................. .................................................................. .................................................................. .................................................................. .................................................................. .................................................................. (ii)

Using the ratio in (i), describe and explain one disadvantage of using a 110 V supply for domestic purposes. .................................................................. .................................................................. .................................................................. ..................................................................

2206-6508 1636

[2]

– 21 – B3.


This question is about electric current and the effects of electric current. Electric current (a)

The diagram below shows the circuit used to measure the current-voltage ( I-V ) characteristic of an electrical component X.

X

On the diagram above, (i)

label the ammeter A and the voltmeter V.

[1]

(ii)

mark the position of the contact of the potentiometer that will produce a reading of zero on the voltmeter. Label this position P.

[1]


Turn over

2206-6514 2133

– 22 –


(Question B3 continued) (b)

The graph below shows the current-voltage ( I-V ) characteristics of two different conductors X and Y.

0.50 0.45 0.40 0.35 0.30 Y X

I / A 0.25 0.20 0.15 0.10 0.05 0.00 0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0 11.0 12.0 13.0 14.0 15.0

V / V (i)

State the value of the current for which the resistance of X is the same as the resistance of Y and determine the value of this resistance. Current:

[2]

... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ..

Resistance: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............ ............. ............ ............. ...... (ii)

Describe and suggest an explanation for the I-V characteristic of conductor Y.

[3]

............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... (This question continues on the following page) 2206-6514 2233

– 23 –


(Question B3 continued) (c)

The two conductors X and Y are connected in the circuit as shown below.

12 V

Z X

Y The cell has e.m.f. 12 V and negligible internal resistance. The resistor Z has resistance R and the potential difference across the conductors X and Y is 5.0 V. (i)

Use the graph in (b) to determine the total current in the circuit.

[2]

............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... (ii)

Determine the resistance R of the resistor Z.

[2]

............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... (iii) Determine the total resistance of the parallel combination of X and Y.

[2]

............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. ....


2206-6514 2333

– 26 –


(Question B4, part 1 continued) Current electricity (c)

In order to investigate the variation of the current I in a variable resistor with the potential difference V across it, a student set up the following circuit.

V A The variation of the current I with V is shown below. V / V

6

4

2

0 0

1

2

3

4 I / A

Use the graph to deduce that, for the battery, (i)

its e.m.f. is 4.5 V.

[2]

............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... (ii)

[2]

its internal resistance is 1.2 . ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. ....

(This question continues on the following page) 8806-6502 2630

– 27 –


(Question B4, part 1 continued) (d)

The battery in (c) is to be used as the power source for an electrical device. The device is rated as 0.8 V, 1.5 A. Complete the circuit below to show how the battery may be connected so that the device operates normally. Calculate the value of any other component you may use.

[4]

device 0.8 V, 1.5 A

............ ............. ............ ............. ............. ........ ............ ............. ............ ............. ............. ........ ............ ............. ............ ............. ............. ........


Turn over

8806-6502 2730

– 28 –



An electric heater contains a number of similar heating elements, connected as shown to a supply of V volts. The switches S1 and S 2 are shown “open”.

0V

V



S1 S2

Each heating element dissipates power P when connected to a supply of V volts. The resistance of each element may be considered to be constant. Complete the table below to give the total power dissipated, in terms of P , for the switches in the positions indicated.

Switch S1

Switch S2

closed

closed

closed

open

open

open

[3]

Total power


8806-6502 2830

– 26 – B3.

This question is in thermodynamics. Part 1

two parts.

Part 1 is


about electrical conduction and

Part 2 is

about

Electrical conduction

In a copper wire the number of conduction electrons is equal to the number of copper atoms in the wire. (a)

State what is meant by conduction electrons.

[1]

............ ............. ............ ............. ............. ........ ............ ............. ............ ............. ............. ........ (b)

(i)

The density of copper is 8.93  103 kg m –3 and its molar mass is 64 g. Deduce that the number of moles of copper in a volume of 1.0 m 3 is 1.4  105.

[2]

............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... (ii)

Estimate the number of conduction electrons in 1.0 m3 of copper.

[1]

............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... (c)

The diagram below shows some of the conduction electrons in a copper wire. The arrows represent the random velocities of some of the electrons.

copper wire Explain, by reference to the motion of the electrons, why there is no current in the wire.

[2]

............ ............. ............ ............. ............. ........ ............ ............. ............ ............. ............. ........


2207-6508 2637

– 27 –


(Question B3, part 1 continued) (d)

An electric field is established inside the copper wire directed as shown in the diagram below. The dots represent electrons. The random velocities of the electrons are not shown. On the diagram below, draw an arrow to indicate the direction of the drift velocity of the electrons.

[1]

electric field

copper wire


Turn over

2207-6508 2737

– 28 –



A typical value for the electron drift velocity in a copper wire is 10 –3 m s –1. In the circuit below, the length of the copper wire joining the negative terminal of the batt ery to the lamp is 0.50 m. S

0.50 m

(i)

The switch S is closed. Calculate the time it would take for an electron to move from the negative terminal of the battery to the lamp.

[1]

............ ............ ............. ............ ............. .... (ii)

The lamp lights in a time much less than that calculated in (e)(i). Explain this observation.

[2]

............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... (iii) Discuss, in terms of the movement of the electrons, the energy transformations taking place in the filament of the lamp.

[4]

............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. ....


2207-6508 2837

– 29 –


(Question B3, part 1 continued) (f)

The diagram below shows part of a circuit that may be used to determine the current - potential difference ( I-V ) characteristics of a lamp.

An ammeter and a voltmeter are required. On the diagram above, draw symbols to show the correct positions of the ammeter and the voltmeter. (g)

[2]

The I-V characteristics for one lamp are shown below.

I / A 0.50 0.40 0.30 0.20 0.10 0.00 0.00

0.20

(i)

0.40

0.60

0.80

1.00

1.20

1.40

1.60 V/V

State a range of values of the current I for which the lamp may be considered to show ohmic behaviour.

[1]

............ ............ ............. ............ ............. .... (ii)

The potential difference across the lamp is 0.80 V. Calculate the resistance of the lamp at this potential difference.

[2]

............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. ....


Turn over

2207-6508 2937

– 6 – A2.

This question is about electric circuits.

(a)


[2]

Define e.m.f. and state Ohm’s law.

e.m.f.:

... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .. ............. ............ ............. ............. ........

Ohm’s law:

............. ............ ............. ............. ........ ............. ............ ............. ............. ........

(b)

In the circuit below an electrical device (load) is connected in series with a cell of e.m.f. 2.5 V and internal resistance r . The current I in the circuit is 0.10 A.

e.m.f. 2.5 V =

r I 0.10 A =

load

The power dissipated in the load is 0.23 W.

Calculate (i)

the total power of the cell.

[1]

............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... (ii)

the resistance of the load.

[2]

............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... (iii) the internal resistance r of the cell.

[2]

............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... ............ ............ ............. ............ ............. .... (This question continues on the following page) 2207-6514 0634

– 7 –


(Question A2 continued) (c)

A second identical cell is connected into the circuit in (b) as shown below.

I 0.15 A =

load

The current in this circuit is 0.15 A. Deduce that the load is a non-ohmic device.

[4]

............ ............. ............ ............. ............. ........ ............ ............. ............ ............. ............. ........ ............ ............. ............ ............. ............. ........ ............ ............. ............ ............. ............. ........ ............ ............. ............ ............. ............. ........ ............ ............. ............ ............. ............. ........

Turn over

2207-6514 0734

– 8 – A3.

N07/4/PHYSI/HP2/ENG/TZ0/XX

This question is about electrical circuits. The graph below shows the I -V (current-voltage) characteristic of an electrical component T. 150

100

I / mA

50

0 0.0

(a)

2.0

4.0 V / V

6.0

8.0

On the graph above, draw the I -V characteristic in the range V  0 to V  6.0V for a resistor R having a constant resistance of 40 .

[1]


8807-6502 0833

– 9 –


(Question A3 continued) (b)

The component T and the resistor R are connected in parallel as shown below. T

R 40  A

B

When a battery of constant e.m.f. E and negligible internal resistance is connected between the terminals A and B, the current in the resistor R is 100 mA. (i)

Calculate the e.m.f. E of the battery.

[1]

............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. . (ii)

Use the graph to determine the current in T.

[1]

............. ............. ............. ............. ............. . (iii) Calculate the power dissipation in T.

[2]

............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. .


Turn over

8807-6502 0933

– 10 –


(Question A3 continued) (c)

In order to reduce the power dissipation in component T, a second resistor R of resistance 40  is connected in series with T. The circuit is shown below. T

R 40  R 40 

A

B

The battery connected between A and B is unchanged. Use the graph to determine (i)

[2]

the current in resistor T. ............. ............. ............. ............. ............. .

(ii)

[2]

the power dissipation in T. ............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. .

8807-6502 1033

– 24 –


(Question B3 part 1 continued) (d)

Using your answers in (b)(ii) and (c)(ii) determine the energy required, in electron volt, to completely remove the electron from the influence of the proton.

[2]

........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. .......

Fields and electric charge in conductors (e)

Define electromotive force (e.m.f.).

[1]

........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. ....... (f)

A filament lamp is operating at normal brightness. The potential difference across the lamp is 6.0 V. The current in the filament is 0.20 A. For the filament of this lamp, calculate (i)

the resistance.

[1]

............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. .

(ii)

the power dissipated.

[1]

............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. .


2208-6508 2433

– 25 –


(Question B3 part 1 continued) (g)

The lamp in (f) is connected in the circuit below. The lamp is still operating at normal brightness.

B

R

The battery B has an internal resistance of 5.0 ! and the resistance R of the resistor is 15 !. (i)

Calculate the current in the resistor R.

[1]

............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. .

(ii)

Determine the e.m.f. of the battery.

[4]

............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. .


Turn over

2208-6508 2533

– 30 –


(Question B4, part 2 continued) Current electricity (c)

Define electromotive force (e.m.f.).

[1]

........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. ....... (d)

In the circuit below the battery has an e.m.f. of 12 V and an internal resistance of 5.0 !. e.m.f. 12 V 

60 !

X

30 !

Y

30 !

60 !

Calculate the (i)

total resistance of the circuit.

[3]

............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. . (ii)

current in the internal resistance.

[1]

............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. .


8808-6502

3031

– 31 –


(Question B4, part 2 continued) (iii) total power dissipated in the circuit.

[2]

............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. . (iv)

potential difference between points X and Y.

[3]

............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. . ............. ............. ............. ............. ............. . (e)

A real (i.e. non-ideal) voltmeter is connected across points X and Y in the circuit in (d). Explain why the reading of this voltmeter will not be the same as your answer to (d)(iv). ........... .............. ............. ............. ............. ....... ........... .............. ............. ............. ............. .......

8808-6502

3131

[2]

  


(Question B1, part 1 continued) 

                                                  







       

[1]

  

       

[2]

           

[3]

    


2209-6508

1230

   B4.

    two  Part 1

Part 1 

  

N09/4/PHYSI/HP2/ENG/TZ0/XX+ Part 2 

 

 

                I           V  



                              

[4]


8809-6502

2628

  


(Question B4, part 1 continued) 

       I  V        V       

[2]

I







V

                     

[1]

                                                                                                   

          4 107                  

[4]

                                                                                                                                                                     

                                         

[4]

                                                                                                                                                                     (This question continues on the following page) Turn over

8809-6502

2728

   B4.

    two  Part 1


Part 1      Part 2     

 

        E1  E 2                            

E1

E2

240 V supply

 E1                        11 10  6   



            

8





E1

2

  

   

[1]

  

    

E1

       

[2]

     E 2            E1         E 2           E1  E 2     

[3]

     


2629


   (Question B4, part 1 continued) 

                  

[3]

      

            

                

                    

[3]



 



 and            

[3]

     (This question continues on the following page) Turn over

2210-6508

2729


   SECTION B

This section consists of four questions: B1, B2, B3 and B4. Answer B1.

    two     Part 1



Part 1 

two questions.

     

Part 2 

    

            

[1]

                                                                  

           

[3]

                                                                                                                                                                     

              –1          

[1]

                                                                  

 resistance

[1]

                                                                  

                          10 –2      10         

[2]

                                                                                                                                       


2210-6514

0922

Past Paper Qs Electric Current-1

Recommend Documents