Physics 2003 P2

SECONDAR SECO NDARY Y EDUCATIO EDUCATION N CERT CERTIFIC IFICATE ATE EXAMINATION

1 1   hours

1.

You M You MUS UST T use use thi thiss ans answe werr bookl booklet et wh when en resp respon ondin ding g to th the e qu ques estio tions ns.. Fo Forr each each que questi stion on,, wr write ite yourr ans you answe werr in th the e spa space ce provided provided and return return the answe answerr boo bookle klett at the the end of the exami examinat nation ion..

2.

ALL WOR WORKIN ING G MUST BE SHO SHOWN in th this is bo book okle let, t, si sinc nce e mark markss wil illl be aw awar arde ded d fo forr cor corre rect ct steps in calculations. calculations.

1.

Table 1 shows the relationship between the temperature, T, of the measuring thermocouple and the thermocouple emf , E,   that is measured by a millivoltmeter.

Thermocouple Temperature

emf  Elm V

TOle

0. 1

0. 4

0. 7

1. 0

1. 4

1. 8

44

118

163

202

247

293

junction

of a

Use the values in the table to plot E against T. Draw your BEST straighfline. (10 marks)

Use your straight line graph to determine thermocouple emf E = O.

(ii)

Use your    straight  T = 2 0 0° C

line graph to determine,

To ' the temperature

Ex'

the thermocouple

at which the

emf when

+ .; .

···r·

·.:

:T :~·;··T· : i:j:::

•••••

t- ••

i!

1

t··

••

... ~ . :.,... !..  j-.

#-

t J.

.. :. ;

;

;.

t · · ·i. .~ . . . r  .; .-

t·   i... t ..

!

...- '· · + · · ~ · · f  .. f ··  t··

t

: :

:

: ~ T · · ;:· r · TT··:··T

::t: : :: · ·

(iv)

Determine the difference between the experimental value as given in Table 1 and  that obtained using the formula in Part (iii),   and explain the significance of this difference.

(v)

Compare a thermocouple and a laboratory mercury in glass thermometer in terms of (i) range (ii) speed of response (iii) sensitivity.

Common Dry Cell

Feature Size/weight

Car Battery Large Heavy

Electrolyte

Ammonium Chloride paste

Emf   

Electrodes

Current Capacity

(b)

 

Lead, Lead Dioxide

Small to moderate

A generator and a battery of secondary cells are connected through an ammeter as shown in the circuit of   Figure 1.

(ii)

Show, on the diagram, the polarity of the ammeter for it to properly measure the current (   1 mark)

(c)

A calculator  battery of  terminal voltage 3 V su pplies a current of 0.1 mA to the calculator  cir cuit.

Write down the   formula that   defines the moment of a force, giving the meaning of EACH symbol and the unit in which it is usually expressed.

(c)

Security guard posts in the Caribbean are usually equipped with a boom and counterweight arrangement as shown in Figure 2. It allows the security   guard to use a relatively small force to raise the heavy boom. ,

Counterweight

FA

Path followed by \, end of boom   ...-... ~

... .

·· ·· ·

.

 A

(

O.3m

Force applied  here

/////////////////

(e)

Use the results of (c) (i), (ii) and (d) above to find  the mass of the counterweight that must  be used if  FA = 25 N is just enough to star t raising the boom. (   3 marks)

(b)

Figures 3 and 4 below are r e pr esentations of curr ent-carrying cond uctor s. Sketch the magnetic field associated with the cond uctor in each of the cases described   below

(ii)

The conductor is tightly wound  into a solenoid  carr ying   current in the directions indicated 

(c)

A flat coil is connected to a small bulb and a diode. The assembly fixed in position near  a current-carrying solenoid is shown in  Figure 5  below.

(i)

What will be the effect on the magnetic flux inside the flat coil if the current through the solenoid is steadily increased?

(iii)

If the diode is removed so that the flat coil is connected to the bulb alone, indicate  by use of a tick ('./) which of the following effects will cause the bulb to glow more br ightly.

EFFECT Increasing the number of  tur n s on the flat coil Placing a piece of soft iron in the core of   the solenoid  Decreasing the rate of change of the current through the solenoid 

YES

NO

State the nature of the unbalanced force which is responsible for circular motion in the following:

(b)

A small bob of mass 0.2 kg is attached to a string oflength 0.5 m and whirled in a vertical circle with a speed of 2.5 m/s as in Figure 6. A

Bob in position A

B Bob attached to string

(i)

Indicate on the d iagram the forces acting on the bob when it is in position C. (2 marks)

(iv)

If the string is released when the bob is at C, what is the tension immediately