Name:……………………………………………………
No. IC:…………………………….
PENGGAL 2 960/2
STPM 2015
JABATAN PENDIDIKAN NEGERI KELANTAN SIJIL TINGGI PERSEKOLAHAN MALAYSIA
PHYSICS 2 (FIZIK 2) MODUL 2 One and a half hours ( Satu jam setengah) Instructions to candidates: DO NOT OPEN THIS QUESTIONS PAPER UNTIL YOU ARE TOLD TO DO SO. There are fifteen questions in Section A. For each questions, four choices of answers are given. Choose one correct answer and indicate it on the Multiple-choice Answer Sheet provided. Read the instructions on the Multiple-choice Answer Sheet very carefully. Answer all questions. Marks will not be deducted for wrong answers. Answer all questions in Section B. Write your answers in the spaces provided. Answer any two questions in Section C. All essential working should be shown. For numerical answers, unit should be quoted wherever appropriate. Begin each answer on a fresh sheet of paper and arrange your answers in numerical order. Tear off the front page of this question paper in your answer sheets of Section B, and tie both of them together with your answer sheets in Section C. Values of constant are provided. Answers may be written in either English or Bahasa Malaysia
For examiner’s use (Untuk kegunaan pemeriksa) Section A (Bahagian A)
Section B (Bahagian B) 16 17 Section C (Bahagian C)
Total (Jumlah) This question paper consists of 12 printed pages and 0 blank pages. (Kertas soalan ini terdiri daripada 12 halaman bercetak dan 0 halaman kosong.) 1
Section A [15 marks] Answer all questions in this section
1
In discussing electric field, the terms electric field strength, electric potential and potential gradient are used. Which of the following statements is correct concerning the terms used? A A unit potential gradient exists between two points if one joule of work is done to move one coulomb of charge between the two points. B Electrical potential at a point is the force exerted on a unit positive charge placed at the point. C Electrical potential and potential gradient are scalar quantities. D The potential gradient at a point is equal to the numerical value of the electric field strength at the point.
2
Which of the following physical quantities does not have a value of zero on the surface of an isolated conductor? A Electric potential at the surface B Current flowing on the surface C Magnetic field near the surface D Electric field along the surface
3
A capacitor with capacitance C is charged to charge Q so that the potential difference across it is V. Which of the shaded areas in the following graphs represents the electric energy acquired by the capacitor? A Q B Q
0 C
0
V
0
4
V D
Q
C
Q
0
C
A parallel plate capacitor is charged in air. The capacitor is later immersed in a liquid dielectric. Which of the following is true?
A B C D
Capacitance Increases Decreases Increases Decreases
Potential Difference Decreases Increases Increases Decreases
2
5
Two capacitors with capacitance of 4 µF and 6 µF are connected in parallel. The arrangement is later connected in series with a third capacitor to produce an effective capacitance of 5 µF. The capacitance for the third capacitor is A B C D
6
3 µF 5 µF 7 µF 10 µF
Which of the following graphs is true of the change in the potential difference V across a copper wire with its electrons moving with drift velocity v? (Assume that the cross-sectional area and the temperature of the wire are uniform) A
V
0 C
v
V
0
V
0
7
B
D
v
v
Q
0
v
A conductor with uniform cross-sectional area A has n free electrons per unit volume. The electrons have drift velocity v in an electric field E. If e is the electronic charge, the current density J in the conductor is given by A Ne B Nev C nevA D nevE
3
8
How much current is flowing through one of the 10 Ω resistors?
A
0.8 A
B
2.0 A
C
1.6 A
D
2.4 A
9
A milliammeter with negligible internal resistance and a full scale deflection of 1 mA is modified for use as a voltmeter with a full scale deflection of 10 V. The correct modification for the required circuit is A a resistor of 102 Ω is connected in parallel to the milliammeter. B a resistor of 103 Ω is connected in parallel to the milliammeter. C a resistor of 104 Ω is connected in series to the milliammeter. D a resistor of 105 Ω is connected in series to the milliammeter.
10
Hall effect cannot be used to measure A the charge density B the magnetic flux density C the mass of charge carriers D the type of charge carriers
11
When a stationary electron is acted upon by a uniform magnetic field, the electron will A move in a circular path B move in parabolic path C not move D be accelerated in a straight line
12
Which of the following produce voltage or current by self-induction? A B C D
High voltage or current produced in a transformer High voltage produced in a Van de Graff generator High voltage produced when the switch in a solenoid circuit is opened Current flows in a copper plate when the plate is oscillating in a magnetic field.
4
13
While a magnet is moved toward the end of a solenoid, a voltage difference is induced between the two ends of the solenoid wire. The voltage difference would be larger if
A B C D E
14
the speed of the magnet were increased. the solenoid contained more loops (while having the same length). The bar magnet produced a stronger magnetic field. All of the above statements are true. Only two of the above statements are true.
A sinusoidal current from an electric source is given by I = I0 sin t Which of the following expressions for the current is true when the amplitude and frequency of the current are increased to twice its initial amplitude and frequency respectively? A I = I0 sin 2t B I = 2I0 sin t C I = 2I0 sin 2t D I = 2I0 sin t
15
The 60 Hz ac source of a series circuit has a voltage amplitude of 120 V. The capacitive and inductive reactances are 890 Ω and 350 Ω, respectively. The resistance is 460 Ω. In Figure above, the capacitance, in μF, is closest to: A 3.0 B 5.8 C 8.6 D 12.0 E 18.0
5
Section B [15 marks] Answer all questions in this section
16
An electron is released from rest in a uniform electric field strength of 7.5x104 V m1 . The distance between the points XY is 0.45 m. -
0.45m
X
Y
+ + + + + + + +
Figure 1 (a)
Find the potential difference between points X and Y.
[2 marks] (b)
Find the change in potential energy of the electron when it moves from point X to point Y.
[2 marks]
6
(c)
If the speed of the electron at X is 2.0 x 106 m s-1, find the speed of the electron at Y.
[3 marks]
7
17
An electric circuit consisting of five resistors and three batteries with negligible internal resistance is shown below.
R1= 2.0Ω I1
R3= 3.0Ω
A I
E2= 4.0V
E1= 8.0V
R5= 4.0Ω R2= 2.0Ω
B
I3 E3= 10.0V
R4= 3.0Ω
Figure 2 (a)
Calculate the currents I1, I2 and I3. [6 marks]
(b)
Determine the potential difference VAB. [2 marks]
8
Section C [30 marks] Answer any two questions in this section 18
(a)
(i)
State the laws of electromagnetic induction, and write down an equation which represents the laws. [2 marks]
(ii)
By using the laws in (a)(i), explain why back e.m.f. is produced in a coil when an alternating potential difference is connected across the coil. [4 marks]
(b) Define self-inductance of a coil, and state its S.I. unit. [2 marks] (c)
An electric current of 1.5 A flows through a coil P producing a total magnetic flux of 0.540 Wb in the coil. If a coil Q is brought near coil P, a total magnetic flux of 0.144 Wb is produced in coil Q. (i) Calculate the self-inductance of coil P, and find the energy stored in coil P before coil Q is brought near it. [3 marks] (ii) Calculate the mutual inductance of coil P with coil Q. [2 marks] (iii) If the current in coil P is reduced uniformly from 1.5A to 0 A in time 0.30 s, what is the induced e.m.f. of coil Q? [2 marks]
19
(a) Define magnetic flux density in terms of the force on a charge. (2 marks) (b) There are two situations in which a charged particle in a magnetic field does not experience a magnetic force. State these two situations. (2 marks) (c)
Figure shows a beam of electrons entering a magnetic field of magnetic flux density 8.4 mT. The electrons are traveling with velocity 3.4 × 107 m s-1 at right angles to the field.
9
Figure 4 Calculate, for the electrons in the field, the magnitude of i) the force on an individual electron. (2 marks) ii)
the acceleration of the electron. . (1 mark)
iii)
calculate the radius of the path of the electrons within the magnetic field. (2 marks)
iv)
Sketch the path travelled within and beyond the field. (2 marks)
(d) Charged particles from the Sun, on approaching the Earth, may become trapped in the Earth’s magnetic field near the poles, as shown in Figure. This can cause the sky to glow. The phenomenon is called the aurora borealis.
Figure 5
Some of the charged particles travel in a circle of radius 50 km in a region where the magnetic flux density is 6.0 × 10-5 T. i)
For a charged particle of charge to mass ratio e/m, deduce an expression for its speed v when traveling in a circle of radius r within a magnetic field of flux density B. (2 marks)
10
ii)
Use your answer to (i) and the information about the path of the particles to show that the charged particles causing the aurora cannot be electrons. (2 marks)
20
(a) In an AC circuit, the supply voltage is given by
where
V in volt and the current is given by I = 0.480 sin (5000t) where I in ampere and t in second. (i)
What is meant by root mean squared (rms) value of the current? (1 mark)
(ii)
Calculate the impedance of the circuit. (2 marks)
(iii) Sketch the phasor diagram for V and I and state the electrical component either RCL, RC or RL. Give your reason. (3 marks) (iv) Calculate the instantaneous and maximum power dissipated in the circuit. (3 marks) (b) A resistor of 6Ω, a capacitor of 3000 μF and an inductor of 5 mH are connected in series. If an AC source of 50 Hz and peak voltage of 240 V is connected to this circuit combination, calculate (i) The total impedance of the circuit. (3 marks) (ii) The resonance frequency of the circuit and explain the energy dissipated during the resonance. (3 marks)
11
Values of constants (Nilai Pemalar) Acceleration of free fall
(Pecutan jatuh bebas)
g
= 9.81 m s-2
Avogadro constant
(Pemalar Avogadro)
NA
= 6.02 x 1023 mol-1
Boltzmann constant
(Pemalar Boltzmann)
k, kB = 1.38 x 10-23 J K-1
Gravitational constant
(Pemalar graviti)
G
= 6.67 x 10-11 N m2 kg-2
Magnitude of electronic
(Magnitud cas elektron)
e
= 1.60 x 10-19 C
Mass of the Earth
(Jisim Bumi)
ME
= 5.97 x 1024 kg
Mass of the Sun
(Jisim Matahari)
MS = 1.99 x 1030 kg
Molar gas constant
(Pemalar gas molar)
R
= 8.31 J K-1 mol-1
Permeability of free space
(Ketelapan ruang bebas)
0
= 4 x 10-7 H m-1
Permittivity of free space
(Ketelusan ruang bebas)
0
= 8.85 x 10-12 F m-1
charge
= (
)
Planck’s constant
(Pemalar Planck)
h
= 6.63 x 10-34 J s
Radius of the Earth
(Jejari Bumi)
RE
= 6.38 x 106 m
Radius of the Sun Rest mass
(Jejari Matahari)
RS = 6.96 x 108 m
of electron
(Jisim rehat elektron)
me
Rest mass of proton
(Jisim rehat proton)
mp = 1.67 x 10-27 kg
Speed of light in free space
(Laju cahaya dalam ruang bebas)
c
= 3.00 x 108 m s-1
Stefan-Boltzmann constant
(Pemalar Stefan-Boltzmann)
= 5.67 x 10-8 W m-2 K-4
Unified atomic mass unit
(Unit jisim atom bersatu)
u
= 1.66 x 10-27 kg
12
= 9.11 x 10-31 kg
