Stpm Trial 2009 Phy Q&a (johor)

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JABATAN PF./A.lARAN JOHOR JABATAN PELAJARAN JOHOR .IARATAN PFJ.A.lARAN .JOHnR .lARA TAN

JAB, 96011 V JOHORJABAT, JAB, VJOHORJABATI JABATAN PELAJARAN JOHOR JABAr..

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PHYSICS

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MULTIPLE - CHOICE One hour and fOrty· five miDutes 3 (1- Hou ..) 4

Instructions to candidates:

DO NOT OPEN TillS BOOKLET UNTIL YOU ARE TOLD TO DO SO. There are fifty questions in this paper. For each question, four suggested answers are given. Choose one correct answer and indicate it on the multiplechoice answer sheet provided. Read the instructions on the multiple-choice amwer sheet very carefolly. Answer all questions. Marks will not be deducted/or wrong answers.

This question paper consists of 30 printed pages and 2 blank page.

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1 If u and v. x and y, I and a represent speeds, distances . time and acceleration respectively. which of the following equations is dimensionally incorrect? A

B

*

@

+ yl = uvt] lI'·u 1 = ax v = at +y// !IX ~ (x + y)/I

Xl

2 The acceleration of a free falling object can be detennined by a photoelectric experi-

ment as follows. The object is released at point P and passing through point X and point Y at time Iz and ly respectively. p

1.

Ught

my

Releasing point p

X

Photo cell

h

tj

Light my

y

0

Photo cell

Earth's surface

The acceleration of free falling object is

-

~

(+j.t, )( t~ -t,J

C

®

=

h' (/, - 1,)

2h ,2 _ / 2

,

'

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3 The graph below shows how force F which acts on an object changes with time I. F (N)

1+

..

--

~

- -... 1(

10

6

15

"

---

2

O':---~'-;;IO:-"":-"!::20""' 1

(s)

If the object moves in a straight line, calculate the change in linear momentum of tile object. A B

® /

.

15kgms' 45 kgm 5. 1 65 kgm s' 70 kg m s"

4 The figure shows a rod pivoted at point P on a smooth horizontal surface.

Two forces each of magnitude 5.0 N acting in opposite directions are applied at the two ends of the rod. The resultant torque on the rod is A

2.5 N m

it

12.5Nm

C

21.7Nm

D 25.0N m

5 Two objects of mass ml and m2 have the same kinetic energy. )fthe momentum of the two objects are 'PI and P1 respectively . then the ratio PI : P2 equals the ratio of A

m, :m 2

B

m 2 :m,

p ::. mv

-p.

P::.

'C' ,Jm: :.Jm; D

.Jm;:,Jm:

!

1

:;: rl.IJ.

'

1")'1 '

/1 ' .

,

~in' , \I;

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6 The fi gure below shows a particle moving in a circle with a constant speed 3.0 m 5- 1, The centripetal fQrce is 100 N. The diameter xv of the circle is 2.0 m. p

x

The work done when the particle has moved through a semicircle XPY is

®

8

OJ

300J

314 J

C

D 628 J

7 Two ri gid bodies P and Q are rotating about the same fixed axis and have angular ve-

locities

and wQ • and angular momentum Lp and Le! respectively. If the values of

W I'

the ratio

OJ" QJ()

and LJi are 1:2 and 2:3 respectively. find the value of LQ .L 1 ~'l.

kinetic energy of object P kinetic energy of object Q A

1

8

"6

23 (

-i)

2

::> ,u....:

}:1..\.L~ D 1.4

"9

An ice skater is rotating with his anns folding inwards. Later the ice skater stretches his anns outwards. Which of the following pairs of quantities will increase?

8

Ci)

l~ ~l,L ~

n'

-, ,,; ("2tJ<3

~

1

, 8 C D

Period of rotation and moment of inertia. Kinetic energy and moment of inertia. Angular momentum and period of revolution. Angular momentum and kinetic energy.

9 A sphere rolls along a straight horizontal platfonn without sliding as shown in the fi gure below. J:: ::


!i0WWW~$//$##&: If the centre of mass 0 of the sphere moves with velocity v m S· I relative to the platfonn. then the velocity of the point Q on the surface of the sphere relative to the platfonn is C

2v

D 3v

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10 The escape velocity (that is the minimum velocity for an objcct to escape to infini7 from the Earth) for an oxygen molecule from the surface of the Earth is 1.1 x 10" m s' . What is the escape velocity at a height ofO.2Rs above the surface of the Earth, where RE is the radius of the Earth? I"). &Mft{ O.~ X

A

@

r

J.P'lV :

10· m 5. 1

I.Ox IO" m s" I.Jx IO"m s· 1

C D

1.~

x 10" m 5. 1

11 An object moves with simple hannonic motion. Which of the following graphs shows the correct variation of velocity with displacement of the object? A v

,10'

1'1/.

B

0Po

71DiSJ)1a~em ent C

Co/

Veloci

~

_--"d_V_ '..,I,,0I:'_I_'Y _T::-:-••

i s p lace m

en t

Velocity

o

i s placcm enl

12 The figure below shows a torsional pendulum which perfonns simple hannonic motion with angular displacement (J. Torsional wire

loZ -

c.

.

~- '

If I is the moment of inertia of the disc about the torsional wire and c is the torque per unit angular displacement acted by the torsional wire to the disc, the period or oscillation of the disc can be expressed as ~

2.z:.J

A

2"~ :0

B

2"Pc

f)

2"~

D

2"~

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13 Which of the following statements is true concern ing an object undergoes simple hannonic motion in a straight line between two points X and Y?

B

Speed is minimum at the middle of the line X V. The total energy is maximum at X or Y. The magnitude of the restoring force is maximum at X or Y.

D

The magnitude of the linear momentum is maximum at X or Y.

A

©

'\

14 A progressive wave is represented by the equation

y = 0.20sin(JOOnt - ; ) , with x and y are measured in meter, and t is measured in second. What is the speed of the wave? o.~o. 20 A

20 m

B

50 m S·I


2f

S·I

'1f

100 m 5. 1 200 m s"

=100

f= "O

15 Which ofthc following statements is Dot true concerning transverse wave? A 8

© D

V r

-=-

Transverse wave can be polarized. y-ray and radio wave are transverse wave.

Transverse wave is produced when air is blown across the end of a resonance tube. Transverse wave is produced when a stretched string vibrates.

16 The length of a pipe which is opened at both ends is 35.5 cm. If the sound speed is 330 m S· 1 and the end correction for each end of the pipe is 1.0 cm, what is the fundamental frequency of the pipe?

"10 ~ u. ·'2<)

®

440Hz

B

452Hz

C

465 Hz

D 478 Hz

.7 A source emits sound of frequency 500 Hz is fixed to the end ofa rod 0[0.5 m long. The rod is rotated in a horizontal circle with angular velocity 50 rad S·I. What is the maximum frequency received by a stationary observer? [The velocity of sound in air "" 340m,'.] A

500Hz

B

537 Hz

©

540Hz

D 579 Hz

f= ~ OO

•

~---o

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18 The graph below shows the variation of potential energy U for an diatomic atom with interatomic separation r.

u

l ,oxto" , =e

'1(, ..

elq.,d e

I

'< lv"

~

€'-

I

Which of the following is not a correct deduction from the graph above?

.-

,

'':

At absolute zero, the atomic separation is ro. For small displacement from the position of r = Yo. atoms vibrate with simple harmonic motion. The positive gradient shows that atoms repel each other for r >

,-

Y.3 K ~~

r" D

Ifa quantity of heat Uo is supplied, the atomic bond will be

broken. 4.

P)

j - 'Jj~

IA-t+e.) U;,"l

--:c t.Yi.

A~IMl>l

19 A mass of2.0 kg is tied to the end ofa steel wire which has an original length of 1.0 and the other end of the wire is fixed at point O. Later the mass is rotated about 0 in a vertical plane with constant angular speed of 4Jr rad S -l • If the cross-sectional area of the wire is assumed constant with a value of 1.0 0101 2, what is the minimum extension produced by the steel wire? [Young' s modulus of steel =2.0 x 101 1 Pa ] 01,

2 , O~IO"

F-e

, A7.

'i'.:;:L'r

A

0.40 mm

B

0.50 mOl

C

1.48 mOl

20 The figure below shows the relationship bcrn'cen the average translational kinetic energy Ek of a monoatomic molecule of an ideal gas at absolute temperature T.

a T

A value for Boltzmann constant can be deduced from the graph above is a

A

b

La

a

B

3b

C

b

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21 The principal molar heat capacity at constant pressure

Cp,m

for an idea l gas is

f

The degrees of freedom for the gas molecules is

A

3

@5

4

B

~R

.I. ],

D 6

22 The figure below represents the variation of internal energy U with temperature T when 5 moles of an ideal gas is heated at constant vo lume. U/J

~- b

---->•. /

r

tl:l. ~ Cl \) ~ [.C.

Co

a

i t'f lZif

' r 5c'1.j1'{l [:).

o

'~ 1'F\j

~ What is the value of the molar heat capacity of the gas at constant volume? A

.

TiK

a

5

a

B

'9 .::.5b

b

D

ob

2

?

L

~. '

,, -

23 A monoatomic gas with volume V and pressure p is compressed isothermally until its pressure becomes 3p . The gas later is allowed to e xpand ad iabatically until its volume becomes 9 V. 1f y of the gas is

A

pV.3p\1,

'i

p

B

~ 3

• what is the linal pressure of the gas?

3

C

P

9

@ .£.

81

24 Two uniform copper rods R and S are joined and perfectly insulated as shown in the figure below. The length ofrod R is twice the length of rod S but the cross-sectional area ofrod R is half the cross-sectional area of rod S.

3

3r(~?"

(t -{)

lnsulal io n

X

KA - ><

(qVf

,,(3-(']

=A£.n - X

to - ~' 2 6 -';,0

1

2 /

lao -9

InsulatIon

I

= 49 - 2.CO

If the free ends of rod R and rod S are maintained at temperatu res 100 DC and 50 DC respectively. what is the temperature at the j unction of rod R and rod S?

~ 60 ' C

B

67 'C

C

75'C

D 90 'C

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16

25 Three point charges -IIlC. +2J.lC. and +3J.lC are placed on a straight line respectively

.1 ~ 10«2 ",(0')

as shown in the figure below.

r2'm1~3""-:;'1

•

,+-7/;£,(2)<.10":)'- •

•

-I~C

+2 IJ.C

4-rc'<..C3""O"')'

+3 J.1C

The resultant force acting on S due to RandTis

2)(

A

('3 XIO"6) ('2" 10 -6)

IO~'

~1L£.

II NtowardsT

B C

15 NtowardsT 15 N towards R .~ 105 N towards R

r \ "\ tu- '

, "

LCl )( 'O",) "l

_

'~x. .

\O-t

-

J

(-;)(10")'

26 The figure below shows a positive plate and a negative plate whic h are parallel. One

electron is released near the negative plate.

E

1T1 0

+

be

I

= -mV'"

1.

Which of the following is true concerning the force F acting on the electron and the kinetic energy Ek of the electron along its motion from the negative plate to the posi-

-

~ivj~ate?

-

,,~

®

Increases Increases

Ek Increases Constant

Constant

Constant

D

Constant

Increases

A

c

F

27 Two identical metal solid spheres X and Y which are charged positively with Ql and (QI > 02) respectively. Which of the foll ow ing statements is true concerning sphere X and sphere Y?

o

o <1,

o

The electric field intensities on the surface of sphere X and sphere Y are

<Ji) C

D

zero. The electric field intensities inside sphere X and sphere Y are zero. The electric field intensity inside sphere X is more than the electric field intensity inside sphere Y. The electric potentials inside sphere X and sphere Y are zero.

28 Which of the following statements concerning an isolated charge conductor which is stationary and non· unifonn in shape is Dot true? A B C

®

The surface charge density of the conductor is uniform. The charge of the conductor only resides on the surface of the conductor. There is no electric field inside the conductor. There is no magnetic field surrounding the conductor.

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29 A 100

18

~F

capacitor is charged and later the charge acquired is di scharged through a charge of ca pacitor after I s? J0 ill resistor. What is the value of the ratio initial charge of capacitor .

•. ~

c.

bG:'lUU ~ .1

U.

<1 =- ~'eA~ , )< •

e

fiG

'" e'

~

e

B

c

In 2

cv,

I - In 2

30 A capacitor of 5 J.1F and a capacitor of 10 J.1F are connected in series with a banery of 12 V. What is the charge at each of the capacitor?

A B C

@

UE

.!QJ!E

10 ~F 20 ~F 40 ~F 40 ~F

20 40 20 40

(I-II,

~F ~F ~F

~F

D.

,

"

•

-l

Cv

Q"

Cv -

Q =C II L r. V .:.. ~ ' C,

31 When potential difference V is applied across the ends of a copper wire which has a diameter d and length I, the drift velocity of electrons in the wire is v. What is the drift

.

velocity of

length

, .,., = -

])t

tenns of v , in a copper wire which has diameter

~ and

!.., and is applied with potential difference 2Vacross its ends? 4

A

v

B

D 8v

2v

:K

'-J 32 If th.e order of magnitude~ for current ~ensity ~d number ?f free electrons per, unit _.~,"-. volume In a metal are 106 A m 2 and 1028 m 3 respectively. what IS the order ofmagmtude ~ ti l for the drift velocity of free electrons in the metal? 3 , _ :L.. !OG

A \;

the electrons, in

B C

®

er--

10' m S-I I Io'm s-

10·2 ms· 1

-.J -

1.\ 'f

n,,' 1029

1= ()" I/e

10~ms-1

33 In the circuit as shown in the figure below, the resistance of the voltmeter is 500 0. , G;. { U

IZO~ looon

looo n

lO Y

What is the reading of the voltmeter?

@

2.SV

B

3.3 V

C

s.OV

D 6.0V

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34 In a circuit as shown in the figure below, cell EI has e.m.f. of 2.0 V and internal resistance which can be neglected. The length of the potentiometer wire AB is 100 em and when switch S is opened, the balance length AX is 75 em. When switch S is closed, length AX is 60 em.

.

I

I' X

A

\:1.:. 1.'7

f2

5

'S-

"5 ll' ~

\ '5 :.

.;---"1

.~

B

f * h a t is the internal resistance of cell £, ?

-;;p

5

A

0.750

B

1.000

@

1.250

D 3.000

35 An electron moves in a straight line in vacuum where there is a magnetic field and an electric field acting perpendicular to each other. If the electric field is removed, the electron will move with

CA) D

same speed in a circle. same speed in a parabola.

C

same speed in a straight line.

D

a lower speed in a circle.

36 The mapnetic field of Earth at the centre of a conductor circular coil of radius 5.0 em is 7.0 x 10· T. The direction of the Earth 's magnetic field is perpendicular to the plane of

') - 7 0)(\ 0 -)' the coil. This magnetic field lJ -

is cancelled by the magnetic field produced at the centre of the coil when a current flows in the coil. What is the magnitude of the current flow?

-

~. ~

A

© D

1,,,"2-

B

1.4A

C

1.8A

(W5.6A

37 When a constant current flows in a moving coil galvanometer, the coil will be deflected by a constant torque because A B

N,40 D P. 0 \)tW-~

0.9A

the coi I is wound round a soft iron core. the coil undergoes critical damping. the coil is placed in a radial magnetic field. the coil is controlled by a helical spring.

38 The magnetic flux density in a solenoid which has 400 turns and unifonn crosssectional area 1 x 10-4 m2 is 5 x 10-5 T when the solenoid carries a current of2 A. If the magnetic flux density of the solenoid is assumed unifonn, what is the self-inductance of the solenoid?

A

0.5

~H

® 1.0 ~H

C

2.0 ~H

D 2.5

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39 A sinusoidal a.c. source with period Tis connected to a pure capacitor. Which of the following graphs best represents the variation of energy per unit time. P. stored in the capacitor with time I in a complete oscillation?

p

p

'.

T

I

)

)

B p

p

D

40 The figure below shows an operational amplifier with open loop voltage gain of 10

5

•

+9V

The voltage supplied is 9 V. If V1 = 0.50 mY and V2 = 0.60 mV, what is the output voltage Vo?

o

9.0V

B

10.0 V

c

19.0 V

D 55.0 V

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41 Lens K. and lens K2 have focal length 10 em respectively. Which of the following arrangements of the lenses will cause paralJellight ray incident at K. becomes divergi ng after emerging

from K2?

?,

42 The figure below shows an air wedge fonned by placing a thin piece of paper be·

tween two thin glass plates at distance 8.0 cm from the line of contact of the glass. Monochromatic light of wavelength 5.89 x 10.1 m is incident nonnally at the air wedge.

Thm P'P"

11 1 1

Light

1d + -I )-,. ')

2Z2~1=~I~14== ~§§§it=. = · = . om-----..j ..

f'f'Thin glass

'.0

If the separation between consecutive dark fringes is 1.5 mm, the thickness of the paper is ~ 0.79 x !a) 1.57 x C 4.71 x D 1.57 x

10" m 10" m 10" m 10~ m

43 Which of the following characteristics will determine whether a wave is longitudinal

wave or transverse wave? A B C

®

-

Reflection Refraction Diffraction Polarization

1:t

44 The optical path in a glass slide of thickness I, is I,. The refractive index of the glass can be expressed as A

c

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45 In a Young's double·slit experiment, the two slits arc radiated from the same light source of so that light emerged from the two slits have

A B C

®

the same speed the same path the same plane of polarization

the same constant phase difference

46 Which of the following graphs best represents the X-ray spectrum produced b.y an X· ray tube at two different potential differences of Va and Vb (Va> Vb ) ? A

B

.~

.~

~

~

~

~

Wavc:lcngth

Wavelength

.~

B

~

~

Wavelength

Wavelength

47 Which of the following is Dot the application of laser light?

(A) B C D

To detect submarine. To cut metal. To measure the distance between Earth and Moon. To perfonn eye and brain surgery.

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48 The stability of a nucleus can be detenn ined by using binding energy per nuc leon as a measurement. Binding energy per nucleon M,V

Nc..

10

8

H,

r

6

.,,

4

2 H

o

50 100 150 200 250 Mass number

~

A

For the most stable nuclide, the quantity is

(i) H

C

maximum for the nuclide in the periodic table. directly proportional to the ratio of pro toni neutron. increases uniformly according to the increase of mass number in the per:iodic table.

D

,

increases unifonnly according to the increase of atomic number in the periodic table. I ,,

N

i'

Q. 49 The radioisotoPes of P and Q have half-lives Tl and T2 respectively with Tl "" 2T2 . The number of nucJei ofP and Q in a sample is the same initially. How long does it take for the number of nuclei P becomes two times the number of nuclei Q ?

T,

A

2T,

B

©

2T,

D 3T,

so A radioisotope of element Z experiences a series of decay until it becomes a stable

isotope of element Z. In this process, the ratio of the number of a-particles emitted to the number of a -particles emitted is

(~ ' - I ' .;~ ,

,

1: 1

B

1:2

-

C

1:4

0

2: 1

-t1r.1.

N ~I\·L"

\"-!c;.:.. -: i' ~ - '-

-,-.

.,., ,

t!~

or,

%011 *This question paper is CONFIDENTIAL until the examination is over

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l ASATAN PF:IA./ARAN lDHDR lASArAN PELA JA RA N JDHOR ./ARATA N PF.I.;1./A RA N .I0HOR .IA RATA N

JAB,'

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lABArAN PELAJARAN JOHDR JABAT!lABArAN PELAJARAN JOHOR JABAT~ l ASArAN PEUJARAN JOHOR lAHAr;.

PERCUBAAN STPM 2009 'JR lASArAN PELAJARAN JOHDR JABArAN 'JR lASATAN PELAJARAN lOHOR lABArAN ')R lABArAN P£LAJARAN JOHOR"JA BA TAN

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JABATAN PELAJARAN lDHDR JABAr/-

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'JR lASArA N PEUJA RAN lOHDR JASArAN

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PHYSICS

JABATAN PELAJARAN JOHOR JABATA~

PAPER 2

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JABATAN PELAJARAN JOHOR JABATA" JR JABATAN PEUJARAN JOHOR JABATAN JABATAN PELAJARAN JOHOR JABATAN PELAJARAN JOHOR JABATAN PEUJARAN JOHOR JABATAN JABATAN PELAJARAN JOHOR JABATAN PELAJARAN JOHOR JABATA N PELAJARAN JOHOR JABATAN

Two aud a balf hours

1

(2 "2 Hours)

Instructions to candidates:

DO NOT OPEN THIS BOOKLET UNTIL YOU ARE TOLD TO DO SO. Answer all questions in Section A. Write your answers in the spaces provided Answer any four questions in Section B. Write your answers on the answer sheets provided. Begin each answer on a fresh sheet ofpaper and arrange your answers in numerical order. Tie your answer sheets to this question paper. All worldng should be shown. For calculations. relevant values of constants in the Data Booklet should be used For numerical answers, unUs should be quoted wherever they are appropriate. Answer may be wrinen in either English or Bahasa Malaysia.

For examiner's use 1 2 3 4 5 6 7

8 9 10 11 12 13

14

Total

;

This question paper consists of 28 priated pages.

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2

- )i..e Seed•• A[40 markr]

*+?I

Answer all questions in this seciion. 1.

I -;,

[,"~r

/l-> C'

UsrSe"'iJZ-

e.../,.n

a+

e-te. "'"",I ·J'v-<:e ctc+ 01"\

J.j 11 _

\~!-f~"')-, ~

[1 mark]

(a) State the Principle of Conservation of Linear Momentum.

.Pt:ioc.iFle...~f. ..~~~... cl... l.i~.....~: ...i? ...~ ...... J\ W~.~.C\ ..of.. .. ~~~~~ ..fh:m .are.. o~ -io qro-!k.r. (b) A buJletofmass 2.0 g is fired horizontally into a block of wood

~ass

placed

on a horizontal surface. The initial velocity oftbe bullet is 500 m 5. 1. The velocity of the bullet which comes out of the wooden block is 100 m s·I.ltls found that the wooden

block slides a distance ofQ.2!Up and stops. Detennine (i) -the velocity of the wooden block at the instant when the bullet emerges from it. triNI'" M'2."" [2 mar.b] (".0)(5= -100) • (H'.>( ID')V....

&:v •

/

.,

(,0 X 'o"') \)1.

-'--

O . <6 ""s-' '
''''' ' Y-

0;

f'0'c.c.: ' 1":>< 6.1- 0

~ (I.OJCO ' ~)'-

[2markr]

/ 2. An object is placed on the principal axis of a thin biconvex lens.The distance between the object and the lens is 20 cm.The lens is made from glass of refractive index 1.65. The image produced by the lens is 0.25 times the size oCtile object. (a) State whether the image is real or virtual?

[1 mark]

........ lI:e....I~... iS....v.i~.:.....?\ ........... !~~.: .................................... . (b) Calculate the focal length of the lens.

[2 markr]

u~ ~o C--'
/

~ _..!-. .... 1. .,. - I.('v ,

I

'-~ ~o

.I.

5

(c) Detennine the common radius of curvature for the surfaces of the lens. [2 markr]

/

/

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3. ' The graph below shows how the acceleration of an object undergoing simple hannonic motion varies with time. Acceleration Ims·2 50

o 0.08 -50

-.--. ~-'

(a) Deduce from the numerical values given on the graph, (i) the frequency

[1 mark]

0 ,04(ii) the angular frequency ro 0 , 0 2.

[1 mark]

/ t.

[1 mark]

(iii) the amplitude Xo of the oscillation. 0 .1"2-

(b)

Sketch a

01',

which shows how the displacement varies with time.

~/",

(I mark]

150

too 50

<>

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A glass fibre of length 0.24 m and area of cross-section 8.0 x 10-7 m2 is stretched until it breaks. Th~ variation with load"F6fthe extension x of the fibre is shown In ffieaiagram below.

4.

: =~ i~L3 1

__+___ . _L__-..I i

I II . I ; O~~2~O---4~O~-+'60~~80~--~

FIN

(a) State with reason whether glass is ductile, brittle or polymeric.

...... :Thr!, ..s~

[2 marks]

.... i~···F~~··! ··~··:11e· e~h ...~ ...

'q .... \ :: .

....§1w.,!13\tt .. li'r:e. ...ClD.J ...~ ... l~ ... OO:t: .. .b:J~ .e)F:\ .. :i&.:.. ../(ne.\ .

(b) Determine the Young's Modulus for the glass fibre.

[3 mar!:!]

"'\, \

\

\

\

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5.

8

(a) What is a multiplier?

[1 markl

.M~\l1p.\(~ ... 6.... 9. .. ~ks", ..~ .. ["' ..Cl'D:.""+.~)< ....... ..... . [1 mark]

(b) State the function of a multiplier?

1O .. JcO~ ·S~~oM?k':':.J'(1/<>~ · I.Plb:'!I~r..:: j :.I (c) A galvanometer of resistance 30 n has a fuU-scale deflection of20 rnA. It is to be converted into a voltmeter of range 0-3 .0 V. Describe briefly, with the aid of a circuit diagram to show how a multiplier is connected to the galvanometer and calculate the resistance of the multiplier required? [3 marb]

Diagram:

-11...

ciruu,.

neC" to,

:~...rn.y,l:tif~······i~.....C;:;tlOIjJdcl:".. '~

:~~~~:: . ~\=:~::::J'~~.::::~:::~~~:':.)<:: : . .:

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(a) State one advantage of using negative feedback in an operational

6.

[I mark]

amplifier.

... ...If. ... wll!... flc\+ .. ~. .a(\.::l.::!®~.:. )( ................................ . (b)

60kQ

20kO

V ..

--=- OV In the op-amp circuit above, the input voltage Yin is sinusoidal with a peak voltage of3.0 V. (i) Calculate the closed loop gain of the circuit. [1 mark]

/ [I mark]

(ii) What is the output voltage, Vo?

/

( iii) Sketch two graphs to show the variation of Viii and Vo with time t on the same axes. [2 marks]

L _' i I i i 1- -T' i --"

C-L...

i

I

I

1

..i

I

Li I

I .

I

I I I

,

r--' - -r+-f-iT--' t-rr - _. --r1--'-f-1 r ! IT I I I !, I ! ! !! I ' I ! I I ii I i i , , i i II =HU-L ! I ! t jtfsl 1! -'- '-r---t,'-+~'-+--T - . _! ' I j--r-T---r-"+'-" .. 1---"1 I

!

r

I.·

i

Ii' ' ! I.

i

! i ~._L--L_..L._L...L_ L-.

Y ---

,.

.i

_1.

!

i

I

!:

i

'f-tT-i-r-1

J

! , 'i i. ,-1-;-+-1--+---11

1

___L ...L_.L. __ _.-1.___.1._-'-_1_.

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12

7. (This question is based on an experiment conducted by NASA on a novel source of energy for a space shuttle.) Above the equator of the Earth. the Earth's magnetic field runs horizontally in the south· north direction.A space-shuttle flying from west to east above the equator cuts perpendicularly across the magnetic field as shown in the diagram below.A small satellite is attached to the shuttle by a very long thin copper cable. It is proposed to use the e.m.f generated in the cable as a source of electrical energy for the shuttle.

Magnetic flux into the paper

x

x

x

x

x

x

x

sate lite x

x

x

x x

x

x

x

x

x

.• x cable

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

shuttle

(8) Explain how is there an e.m.f. generated in the cable?

[1 mark]

.....~ ..:k...o::ili\~ ... h .. tP.l:-.... i[\:j\.l\~,."~ ...~ ... ~ndtG ···~·····~VS ....i:o ... ~.....?:.rr.·..f. .... j.(\)Ai\.ctAble..~ .. ......... (b)Calculate the magnitude of this c.m.f. using the following data:

Cable lenath - 20 Ian Speed of shuttle and satellite = 7.0 Ian " Horizontal component oCdle Earth's magnetic flux density = 6.0 x 10-5 T.

I

[3 marb)

/

(c) State the direction aCthe generated'c.m.f.

[/ mark)

!

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8. (a). Explain briefly what is meant by nuclear fusion .

[I mark]

.NM.~ .. -Mtoo ... j's... a. .. ~(\ .. ~~ .... ~ ...q;\pm \/ WIlI$.ls.. ..~\')~.~~r: . ~.~ ~ I t>tbm;\ ~n 0, clec1:rt>[15' (b). A carbon isotope ItC is bombarded with a proton to produce an unknown nuclide, X.

(i)Write 8 nuclear equation to represent the above reaction and identify the unkown nuclide, X. [2 marks]

,~

6 C

1 J.\ -t

,

-?> n

f

X

V

f'-..

.fI.

(ii) Calculate the energy released during the reaction.

Massar ':C =" 13.oo3355u , massof:H Mass of unknown nuclide,X ' = 14.003074 u lu = 931 MeV

=

l.oo7825 u [2 marks]

E = rnc."2. E' (1 3.00"':;.55" )(3. 00 )(10'8) fOr

, ,. n

, I

1-\ ;

X 10' 1\

-10"'. '5b

S- '

5:=",c." E:- (1 , 001825)(3 . 00XIOls ,~

= "l, 01 x 10 n

For

I

x."

>

.lI ('(\ '

~

l

5 b ".- '

E ·",,-'-

g

5.. (1 tj.,OO3.Oi4-)C3 ' c)O'olID )L = 1'''bX{OIS 4t- r-,3 5 6.$-' ( I. \'

>l

1 10 <;1)+

(q ,01 >"10 I~} \ '26

X 10

18

.'

\\

.

\.').6"-16'" ~ E x

--- No ene<3':J releosed J. .....":3 -Ht.... reo.dton . 96012 ·This question paper is CONFIDENTIAL until the examination is over

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16

SeetiOD B [60 marks]

Answer any four questions in this section [I mark]

9. (a). What is meant by centripetal force ?

(b). A student suggests that for a body to perfo.nn circular motion, the centripetal force acting towards the centre of the circle is balanced by the centrifugal force acting outwards away from the centre of the circle. Comment on the above statement [2 marks]

(e). A car goes over a hump of radius of curvature )0 m. What is the maximum speed of the car so that it is always in contact with the road ? [3 marks]

(d) (i) State Newton's Law of Universal Gravitation.

[I mark]

(ii) A satellite of mas~s round a planet of mass..MJ.n an orbit of radiu~

If G is the universal gravitational constant, what is the gravitational force of attraction between the planet and the satellite? [2 marks]

(e) A satellite of mass 150 kg goes round the earth in a circular orbit of radius twice the radius of the earth. Calculate . (i) the centripetal force acting on the satellite. (n) the orbital period of the satel1ite.

[3 marks] (3 marks]

(Radius of the earth : 6.38 X 10' m)

F' -(i M:!L r"l. I.-t'

\p

-~~

t-~~

F-~~ ~

Dr

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10.

(8) Metals are good conductors of both heat and electricity while good thennal insulators. are also good electric insulators. Ex.plain why? [3 marks] (b) The ~ through a well-lagged metal rod at steady state is defmed b) the

equationl

~ = - 1c.4

B

where Q i5nle quantity of heat flow, k is the thennal conductivity oftbe metal, A is the

- - - dB -cross-sectional area of the rod and dx is. the temperature gradient along the rod. ~

(i) Explain what do you understand by steady stale and lemperature gradient?

[2 marks] (ii) Based on the statement in (a) above, state the quantities in electric conduction for metals that are analogous to rate ofheal flow and temperaIure gradient in thennal

[2 marAs]

conduction for metals.

(iii)Hence write an equation for electric conduction that is equivalent to the equation of

heat flow as in (b) above. Explain the symbols used in your equation. [2 marks] (e) The diagram below shows two rods of the WIle length, ~and diamet~ but made from two different ma~ P and Q. They are placed end to e~theentact and weILlaggedantretJ:si(feS. Theouterends of P and Q are kept a~ IOOGC respectively. The thennal conductivrty of P is four times that ofQ.

~ ~

O·C

~IOOOC ~

laggging

(i) Detennine the steady-state temperature at the j ointed-end.

[3 ma,.ks]

(ii)Sketch a graph to show the distribution of steady-state temperature along the who le [3 marks] jointed rod.

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X 11.

(a) State two conditions necessary to produce a well-defined stationary wave using two separate sound sources. [2 marks ] (b)The equation of a stationary wave on a stretched string is given as:

y = 0.1 sin 2501 cos SOx where distances are in metres and time is in seconds. (i) Calculate the frequency afthis wave. (ii) What is the distance between two neighbouring nodes along this waves.

[2 marks]

(iii) Calculate the speed of the wave in this string.

[2 marks) [1 mark]

(e) (i) What do you understand by inteiference.

[1 mark]

(ii)State two conditions necessary to produce a welt·defmed interference pattern . [2 marks)

(d) The apparatus ofa Young' s double-slits experiment is set up as shown below. Gis equidistant from the double·slits 8. and 52' H is a point on the screen when the light waves from 51 and S, interfere with a path difference of

~.

Hly

1 5 ,1

~- ------i--------------------------------G 1

5, 1

•

o

(i) What is the type of interference observed al G and at H respectively? [2 marks] ( ij) If the distance S.Sr 1.0 mm, 0=] .50 m and the wavelength of the light, A. is 600 nm,

calculate the value of y.

[3 marks)

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22

(a) A stationary negatively-cbarged particle experiences a force in the direction of tile field in which it is placed. State and explain, whether the fie ld is magnetic, electric or

gravitational.

[2 marks ]

(b) Calculate the magnitude oftbe electric field strength required to maintain an electron in a fixed position in the gravitational field of the Earth, at its surface. (Takeg=9.8 1 ms·2 ; mass of electron =9.1 x 10.31 kg)

[2 marb]

(e) Neon-20 atoms are ionized by the removal of one electroo from each atom. For a Neon-20 ion, (i) state the charge on the ion. (ii) calculate its mass. (d) The neon ions in (e) are accelerated from rest in vacuum through a potential difference of 1400 V. They are then injected into a region of space where there are unifonn e lectric and magnetic fields acting at right angles to the incident direction of

motion of the ions as shown in the fo llowing diagram. The electric field has field strength E and the flux density of the magnetic field is B.

/" Region of Wlifonn "

electric and magnetic fields

Path of neon ions

(i) Draw and indicate clearly the directions of the electric and magnetic fields so that the ions pass through undeflected through the region. [2 marks] (ii)Calculate the speed of the accelerated ions o n entry into the region of the electric and [2 marks] magnetic fie lds. I

(iii) The electric field strength E is 6.2 X 103 Vm- • Calculate the magnitude of the magnetic flux density so that the ions are not deflected in the region of the fields.

[2 marks] (e) The mechanism by which the neon atoms in (c) are ionized is changed so that each atom loses two electrons. State and explain what change occurs in: (i) the speed of the ions entering the region of the electric and magnetic fields as in (d) above. [I mark] (ii) the path of the ions in the region of the electric and magnetic fie lds.

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(8) What do you understand by (i) de Broglie's relationship (ii) wave-particle duality ?

[2 marks]

(b) What is the de Broglie wavelength of an electron which has a kinetic energy of SO eV ?

[2 marks]

(c) Explain the differences between the production of the continuous spectrum and the characteristic spectrum of X-rays.

[4 marks]

(d) Sketch a suitable graph to show the continuous arid characteristic line spectrum of the X-rays produced when a metal target is [2 marks]

bombarded by energetic electrons

(e) Explain why for an electron of energy E. the wavelength of the X-rays produced has a minimum value. A..,.

[2 marks]

(t) Calculate the shortest wavelength of X-rays emitted. by electrons striking the surface of a 20kV television picture tube.

[3 marks]

[m. = 9.11 x

jO"lI

kg

Planck con_t= 6.63 x 10·"]

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26

(8) Define the half-life and decay constant of a radioactive substance.

[2 mar"]

(b) Naturally occurring radium-226 with atomic Dumber 88 produces the radioactive gas radon-222 by alpha decay. (0 Write an equation for the decay process [I mark] (ii) Calculate the total kinetic energy of the decay products in MeV [3 mar"] Mass of radium = 226.025402

Massofbelium'" 4.002603 u

U,

mass of radon = 222.017570 u

lu = 931 MeV

(e) The bombardment of a beryllium nucleus by an alpha particle produces a fundamental

particle X. as follows

.

a+ 9 8e ---+

,

12C+X

(i) Complete the above equation

[2 mar"]

(ii) What are the alpha particle and X ?

[2 mar"]

(iii) State two important properties which makes X difficult to detect

[2 mar"]

(d) An ion of unknown atomic mass is mixed with I!C in a mass spectrometer. The radii of curvature of the tracks of the ions and '!C are 26.2 em and 22.4 em respectively. What is the identity of the unknown ion? State any assumptions that you make.

[3 mar"]

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CONFIDENTIALSUGGESTED ANSWERS AND MARKING SCHEME JOHOR STPM PHYSICS TRIAL EXAMINATION 2009

PAPER 2 SECTION A Question Number 1. (0)

(b)(i)

(b)(ii)

Suggested Answer

Marks

The Principle of Conservation of Linear Momentum states that the total linear momentum of a system is constant ( or conserved) if there is no external force acting on the system.

1

conservation of linear momentum 2,Ox 10" x 500 = 1.0 (v) + 2.0x 10" x 100

1

v= 0.80 m 5 . 1

1

Loss in K.E wooden block=work done against constant or average

frictional force

2, (0)

(b)

1

.!.(1.0)(0.8) ' = FR(0.20) 2 => FR = 1.6 N

1

image is real

1

v =0.25(20)

=5.0 em

1

1 1 1 1 1 -=-+- = - + J U v 20 5.0

1

J=4.0cm 1

1

1

/

T.

T2

- = (n - 1)(-+- )

1

I 2 = (1.65 - 1)4.0 r

1

-

1

r l = T2 = 5.2cm

3. (o)(i) (ii)

1 T

1 0.04

f= - = -- =25Hz

50 fi

1

angular frequency : w =2m = 157=160 rads"

1

amp I·Itude , "0-- -G,, = ( 50)2 = 20 . x 10-' m

1

IV

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x (x10·"

(b)

2.0....1\ _...1\.... 1\ . . . . . . Us U °V O~~

0.12 ·2.0 ........ ...... .... .............................................................. .......................... . 4. (a) (b)

Brittle show no plastic deformation before it breaks

E= FL xA

60xO.24 3x10·4 x8x10 7 =6.0xI0 IO Nm· 2

= -....:..:.,:.:...:..::'-'-""""

5. (a)

A multiplier is a resistor of very high resistance connected in series to a

2

1 1 1 1 1 1

galvanomet~r .

(b)

The function of the multiplier is to reduce the incoming current down to the maxirnu"m current that can be carried by the galvanometer.

1 OR The function of the multiplier is to convert the galvanometer into a voltmeter.

(c)

Irsd

i---{

•

J=I ftd =

V=3.0V

V = 3.0 = 0.02 r+Rm 30+Rm

30 + R. = 3.0 = 150 => R. = 1200 0.02 The multiplier is connected in series to the galvanometer.

6. (a)

to reduce the distortion of the output or to reduce the gain

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Gain

(ii)

1

Rf 60 A = I + -=I+ - =1+3=4 20 R,

1

'...'-:. 1( ..)0'" ,_.....' :.

..

12

""'-5 :.:r

..

/ ./ / --".,-

,)

-;:... -,~.

' .

'.

,

..-

. ........

'- "'-"~'"

. /

(e) 8, (a)

(b)(i)

\

",

,

,

..

.

-

./

. -"'

.

.:

Til'n

.""

There is change in magnetic flux-linkage

E = BIv

=6.0 X 10-5 X 20 X 103 X 7 X 103

, 2

1 1

=8.4 x 10'V direction of generated e.m.f is from"space shuttle to satellite.

1 1

Combination of 2 lighter (or smaller) nuclei at very high temperature to produce a heavier (or bigger) nucleus accompanied with the release of a lot of energy.

1

, ,

,

J3C+ lH-+14X

1

,

1

,

14X

(ii)

-

..:.:........ .. .

-12

(b)

,. .""11".

\~

-,;>

7. (a)

1

Output, V, = AVm = 4(3 .0) = +12.0V = +9.0V(saturation)

is

J4N

Mass defect,

MI = (13.003355 + 1.007825)u - 14.003074u

MI=8. 106 x lO"u Energy released, Q = 8. 106 x 10-' x 931 = 7,55 Me V

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SECTION B 9. (a) (b)

Centripetal force ::: force that causes a body to move in a ci rcle , and its direction is always towards the centre of the circle .

1

The statement is false .

1

If the two forces balance each other', the resultant force;:: O. According to Newton's first law of motion , the body will move in a straight line with constant velocity. That is the body will not perform circular motion.

1

(e)

R

ill mg Resultant force towards the centreof circle ;:: mg - R

1

mv'

Hence mg - R;:: - r

1

For maximum v, R::: 0

v::lrg (d)(i)

( ii)

;F81 ~~s -'

,9 "I ",,-'

1

Newton's Law of gravitation states that the force between two masses is directly proportional to the product of the masses, and is inversely proportional to the square of the distance between them .

1

The gravitational force of attraction is F= G Mm

1

r'

(e)(i)

F; G Mm . r

F; gR'

,.

X

4R'

GM = gR2;

150

9.81x150 4 ; 368 N

r = 2R

1

;

(ii)

F = mr a/

368 ; 150 x 2 x 6.38 x 10' ",'

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5

1 Period T

(iii)

= 2"

(iJ = 1.435 x 10' s.

1

K.E~ - mv

1

2

K.E

10,(0)

(b)(i)

J

~-m(r (iJ)

1

1

1

2

~ ~(150)(2 x 6.3 8 x 10')' (4.38 x 10-')' ~ 2.3 4 x 10' J

Heat and electric conduction in metals are both caused by the many free electrons that moves with high mobility.

1

There are no free electrons in thermal and electric insulators .

1

Thus thermal and electric insulators are poor conductors .

1

Steady state is' achieved when the temperatures at all points along the metal rod are stable and not changing.

1

II' we'

1

2

Temperature gradient is the difference in temperature-per unit length

c~,

along a conductor.

tlx

I

L iI) (iii)

Current, f

.

dC/ , Qll t~l ( -~ r -pAl )" ~ '\' . o(;t

l ' -Cl.

v

1

J,..uJ

kA.1& ~

..L

pA ~

1

K

where: 1 is the current in the tlowinlln the conductor, p is the resisti vity of the material conductor,

(c)(i)

V is the potential gradient along the conductor. I rate of heat flo w in P=rate of heat flow in Q V, .

I

"

111.. ;.,

1

V, l(q;i

=> 4kA(8-0) =kA(100-8)

,

1

1

I

v

t

'-

) p-., 1

-1'& : , b

t

t

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6

TemoeaturefC

100

----- ------- -- ---- 1-------- --- ------ 3

....•,

25

,

, . O~~------~----------r_-+

length

21 p

11 .(a) (b)(i)

Q

Supposition of 2 identical waves travelling in opposite direction. Amplitude of both waves are the same or almost the same

1

Compare to stationary wave equation y = A sin OJ' kos 2m ,l

'" = 2nf = 250

f (ii)

1

1

250

= - - = 39.8 = 40Hz

1

2"

2" = 50

1

,l .

2" = O.13m = 13.0em

,l = -

50

distance between 2 neighbouring nodes:;:: A. =

2

(iii)

speed of wave . v=jA=(40)(0.13)=5.2ms- 1

!2 = 6.5cm 2

~ X "1\ "",,~(o .;v

1 1

(c)(i)

Interference is the superposition of two coherent waves to produce points of maximum and minimum amplitudefintensrty.

( il)

Two conditions for well·defined interference are: -both waves are coherent and same or almost the same amplitude .

2

Interference at G is constructive interference. Intererence at H is destructive interference.

1 1

(d)(i)

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CONFIDENTIAL· (ii)

1

At H, is first minimum where m=1

(m - )I,)DA y=

d

(1- )1,)(1.50)(600 x W ' ) = 1.0 x 10- 3

1 '1

a) The stationary negative charged particle will move in the direction of the gravitational field. 0 e

12.(a)

1

J "'1 The stationary negative charged particle will move oPPosite in direction to an electric field and will not move in a magnetic field. Upward electric force

(b)

=downward gravitational force

eE = mg

1

1

\ 1 (e) (i)

(ii) _

charge on Ne ion

=+1 .6 x 10.19 C

. M 20 x 10-3 mass of Ne lon, m =_ r= 23

N,

6.02x 10

1 26

3.3x IO - kg

2

(d)(i)

Path ofNe+ ions

OR

E

Path of Ne+ ions

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CONFID ENTIAL· (ii)

1 , -my = eV 2

1

V=~2ev

=,12(1.6 X I0-" )(1400) =2.2x l0' ms -' m V 9.1 x lO-31 '

(iii)

(e)(i) (ii)

13.(0)(1)

1

electric force = magnetic force

eE =Bev

1

8=£=6.2 x l 0' =2.8 x l 0-' T v 2.2xl0'

1

Charge doubled, speed

v increased

by

J2 times.

1

Magnetic force> electric force, ions deflected from original path.

1

The de Broglie's relationship gives the value of the wavelength )_

h

related to a particle of linear momentum p in the equation A. = -

p

where h is the Planck constant

(ii)

(b)

The wave-particle duality refers to the wave nature of a particle under certain specific conditions and the converse is also true

.!. mY' = 50 ( 1.60 x. W " 2

6.63xl 0-" mv (e)

= 1.74

A. = X

1

)

mv = ~2x50(1. 60xlO -")m de Broglie wavelength

1

1

h mv

10.10 m ;

me =9.11 x 10.31 kg

Continuous spectrum is produced when fast electrons from the cathode are decelerated on collision with the target . The decrease in energy of the decelerated electrons is radiated as photons in the continuous spectrum .

1

2

Characteristic X-ray is produced when a vacancy in the inner shell (e.g . K-shell) of the target atom is filled by an electron from a higher shell .

The difference in energ y of the electron is radiated as a characteristic X-ray photon.

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CONFIDENTIAL"

(d) /

Intensity line spectrum continuous spectrum

2 wavelength

(e)

When an electron collides with a target atom , the electron will decelerate and is stopped. The loss of aU the kinetic energy E of the electron in a

1

single collision with the atom means that the X- ra y emitted has

\

. h maxImum paton energy 0f -he-

1

A"" (f)

he

eV= - -

1

..t,Nn

A.

=

lIua

he

1

20xlO J x1.60xlO-'9

= 6.22 x 10"'m

14. (a)

1

Half-life : the time taken for the number of radioactive atoms in a sample to decay to half of its initial number.

1

dN decay constant =

(b)(I) (ii)

~: Ra

-----+

dl N

1 1

2~ Rn + ; He

Mass defect /:, m = 226.025402u - (222 .017570 + 4 .002603)u

= 0.005229 u

Total K.E

(c)(I)

4 l

a +

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= 0.005229 x 931

1

= 4 .88 MeV

1

9S e •

--.to

12 C •

+

IX

0

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!O

CONFIDENTIAL(ii)

alpha particle ; nucleus of helium

~x (iii) (d)

1

: Neutron

1

neutron is not charged and does

mv'

~-

~ot

cause ionization

= 8qv

1

r

m = Bq r v Assumption: Ions of the element and ions of C-12 have the same charge , then m

IX:

)

=

26.2 x 12 22.4

0::

r

= 14

The element is nitrogen, N

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r

Hence mass number A

A ,

2

1