peperiksaan cubaan sem2

8/17/2019 peperiksaan cubaan sem2

1/8

SULIT

960/1

APRIL 2014

PEPERIKSAAN PERCUBAAN

SIJIL TINGGI PELAJARAN MALAYSIA

SM TINGGI KOTA KINABALU

PHYSICS

PAPER 1

One ho! "n# " h"$% ho!

In&'!(')on& 'o ("n#)#"'e&*

DO

NOT

OPEN

THIS

BOOKLET

UNTIL

YOU

ARE

TOLD

TO

DO

SO.

There are %)%'+ questions in this paper. For each question, four suggested 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 "$$ questions. Marks will not e deducted for wrong answers.

A!"h"n ,e-"#" ("$on*

JANGAN BUKA BUKU SOALAN INI SEHINGGA AN.A .IBENARKAN BERBUAT

.EMIKIAN

Ada $)" -$h soalan dalam kertas ini. !agi setiap soalan, empat cadangan "awapan

dierikan. #ilih &"' "awapan yang etul dan tandakan "awapan itupada helaian "awapan aneka

pilihan yang diekalkan.

!aca arahan pada helaian "awapan aneka pilihan itu dengan teliti.

$awa &e" soalan. Markah tidak akan ditolak agi "awapan yang salah.

!uku %ata diekalkan.


2/8

2

1. Which of the following statements explains correctly the decrease in

resistivity of an intrinsic semiconductor when its temperature increases?

A The drift velocity of the charge carriers increases with temperature.

B The number of charge carriers per volume increases with temperature.

C The rate of collision between the charge carriers and atoms increases with

temperature.

. The amplitude of vibrations of the atoms of a semiconductor increases with

temperature.

2. The diagram below shows an electron moving at constant speed through a region in a

uniform electric field & .

Electric field &

Electron

Which of the following is the most probable path of the electron ?

A B

C .


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3

. What happens at the moment when a circuit consisting of a resistor! a capacitor and a dry

cell connected in series is turn on?

A The current flowing in the circuit is maximum

B The capacitance of the capacitor is minimum.

C The voltage across the resistor is "ero.

. The power loss in the circuit is minimum.

#. The current density in a conductor can be defined as

A charge that flows per unit time

B charge that flows per unit volume

C electric current that flows per unit volume

. electric current that flows per unit cross sectional area

$. The e%uation which relates the electrical conductivity & of the material of a conductor with

other %uantities is σ = ne

2t

where n! e an m are symbols which carry the usual

meanings. t in the e%uations represents

A the thic'ness of the conductor

B the mean distance between ad(acent atoms in the conductor

C the mean time between the collision of free electrons with lattice atoms

. the mean time for a free electron! to move from one end to the other end of the

conductor

). *n electric circuit is shown below.

1#Ω

1+Ω '

2.+ *

#Ω

if the current flowing through the 1+ , resistor is 2.+ *! the current ' flowing through

the 1# , resistor is

* +.#+ * - +.$) * 1.33 * / 1.#+ *

m


4/8

#

0. n the circuit shown below! is a 1++ cm long wire of a potentiometer. E is a dry

cell of emf 1.# 4 and internal resistance +.# ohm. 5 is a resistor of 2.+ ohm. When switch

6 is opened! the balance point 7 from is )# cm.

5

When switch 6 is closed! the new balance point from is

A 3+ cm B + cm C $+ cm . )# cm

8. The diagram below shows four parallel wires vertically through the four vertices of a

s%uare W9. These wires carry currents of e%ual magnitudes in the direction shown.

M1 2 2

PO

3

4

N

2 Y

The direction of the resultant magnetic field at the centre : of the s%uare is

A :; B :< C :7 . :=

E >

6


5/8

6

1+. Which of the following is no' true about selfinductance of a coil?

A The selfinductance is e%ual to the rate of current change in the coil B The bac'emf in the coil depends on the selfinductance.

C The selfinductance depends on the number of turns of the coil.

. The selfinductance is e%ual to the ratio of the total magnetic flux to the current

flowing in the coil.

11. Which of the following graphs shows the variation of the reactance ( of a capacitor

with the fre%uency f of an alternating potential difference which is applied across it?


6/8

12. f a stationary electron is sub(ected to a uniform magnetic field! it will be @

A accelerate in the direction of the fieldB caused to move in a circular path

C caused to oscillate about a fixed point.

. unaffected.

13. When the load of an electric motor is increased! the speed of rotation of the motor decreaseswhile the current that flows through it increases. Which of the following statements explains theincrease in the current ?

A The resistance of the coil of the motor decreases.B The power dissipated in the coil of the motor decreases.

C The bac' emf induced in the coil of the motordecreases.

. The voltage supplied to the motor increases.

1. *n alternating current ' which flows through a # Ω resistor is given by ' ) *

sin+t. f ' is in amperes and t in seconds! what is the mean power generated in theresistor?

A # W B 2+ W C + W . 0+ W

1#/ *n alternating current ' represented by the e%uation ' ) sin 1++t flows in a resistor of #.+ A. f ' is in ampere and t in seconds! the mean power dissipated in the resistor is

A 1+ W B 2+ W C + W . 1$+ W


7/8

BET:< -1# ;ar's

*nswer all %uestion in this section

1$. * +.# mm diameter copper wire carries a tiny current of 2.+ C*. alculate Dnumber of the free electrons per unit volume of cooper 1+28 m3 !

resistivity of cooper 1.) x 1+0 A m F

aF the drift velocity of electron in the wire 3 mar's

bF the current field 2 mar's

cF the electric field 2 mar's


8/8

1). n a circuit an a.c circuit the supply voltage is given by 4 2+ sin #+++t and the current in the

circuit is given by +.0+ sin D#+++t G HI2 F.

a) /etermine the reactance of the circuit 2 mar's

b) B'etch the phasor diagram of 4 and 2 mar's

c) Btate the electrical component in the circuit and give a reason to support your answer. 2 mar'

d) Why is electricity transmitted in the form of alternating current? 2 mar'

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