1

PENGGAL 2

960/2 STPM 2015

JABATAN PENDIDIKAN NEGERI KELANTAN

SIJIL TINGGI PERSEKOLAHAN MALAYSIA

MARKING SCHEME

PHYSICS 2 (960/2)

MODULE 1

2

Marking Scheme

1. A 6.B 11.A

2.B 7.A 12.A

3.D 8.A 13.B

4.B 9.A 14.D

5.A 10.C 15.D

16. (a) (i) Sphere X,

0

1

2

10

11

4

r

QE

1 M

Sphere Y,

0

2

2

20

22

4

r

QE 1 M

The ratio

2

1

2

1

E

E 1M

(ii) Charge flow until the electric potential of the spheres are the same.

Hence 12

1 V

V

1M 1M

(b) ErV

Since 12

1 V

V

So 1

22

11 rE

rE

from 2

1

2

1

E

E

Then 122

11 r

r

1M

So

1

2

2

1

r

r

1M

Total 7 M

3

17 (a) dIE L

dt

Symbol explained

E = induced e.m.f. in a coil

dI

dt= rate of change of current in the/a same coil

Alternative 1:

N = LI N is the number of turns/loops

is the magnetic flux through a coil L is the self-inductance I is the current flowing in the the/a same conductor/coil

Alternative 2:

= LI

is the magnetic flux linkage L is the self-inductance I is the current flowing in the the/a same conductor/coil

Alternative 3:

N = LI N is the number of turns/loops

is the magnetic flux through a coil L is the self-inductance I is the current flowing in the the/a same conductor/coil

Alternative 4: The ratio of (magnitude) of induced/back e.m.f in a coil to the rate of change of current in the coil.

2M/0

(b) (i)

dILdt

f iI IdI

dt t

If = 13 4(2)

= 5.0 A

Alternative 1:

dI

Ldt

f iI IdI

dt t

= 21.0 A

1M 1M 1M OR 1M 1M 1M

(ii) = LI

= (0.26)(5.0) = 1.3 Wb or 5.5 Wb

1M 1M 1M

Total 8 M

4

18 (a) (i)

Hzffrequency

f

50,

3142

1M

(ii)

V

VVrms

14.1

2

0.2

1M 1M

(b) (i) When ac flows in the inductor:

magnetic flux linkage through the inductor varies sinusoidally.

the change in magnetic flux linkage produces a back-e.m.f. // electromagnetic induction occurred inside the inductor. According to Len's law: the direction of the back-e.m.f. opposes the supply e.m.f

1M 1M 1M

(ii) VVE appliedback 0.1

1M

(iii)

A

A

fL

V

X

VI

RMS

L

RMSRMS

9.0

)105502(

41.1

2

3

1M 1M

(c) (i)

Axis : 1M

Magnitude : 1M (by comparindg) Shape within Period : 1M

3M

(ii) During t = 0 to T

4

1 : Power P is negative

1M

5

power is returned completely by the inductor to the supply.

During t = TT2

1 to

4

1: Power P is positive

-power supplied to inductors. Hence mean power = 0.

1M 1M

Total 15 M

19 (a) The normal operating voltage is 240 V.

When a voltage of 240 V is supplied, the power dissipated by the electric iron is 1.2 kW

1 M 1M

(b) (i) The average/mean velocity of the charge carrier/electron/ taking into

consideration the collision with positive ions 1

along/opposite direction of/in an electric field/potential difference applied 1

1M 1M

(ii)

mV

AN

nV

AN

m

363.5 108900

AN

(NA) = 8.44 1028 m3

I nAve

I

vnAe

28 3 2 19

0.15

8.44 10 (1.0 10 ) 1.6 10v

Cross sectional area

= 3.54 10-6 ms1 or 3.5 10-6 ms1 1

1M 1M 1M 1M 1M 1M

(c) (i) Current density

A

IJ

= 3 2

15

(4 10 ) Area

= 9.375 105 A m2 or 9.4 105 A m2 1

1M 1M 1M

6

(ii) The resistance of the copper rod

A

lR

8

3 2

1.69 10 60

(4.0 10 )

= 6.34 102

1M 1M

Total 15 M

20 (a) (a) The hall effect is the phenomenon in which a transverse voltage is set up in a conductor carrying a current in a magnetic field

Place a piece of n-type or p-type semiconductor in a magnetic field B Let a current I flow in the semiconductor, A millivoltmeter connected across XY of the semiconductor records the Hall voltage Or

2M 1M 1M 1M Or 3M

(b)

(i) Voltage Hall HV

ME FF

BeeE

acAneA

I

c

VE H ,, where

Bnea

Ie

c

Ve H

1M 1M 1M 1M

7

nea

IBVH

(ii) Polarities of HV ; Front edge is negative, Back edge is positive

Or

2M OR 2M

(iii) The Hall effect Potential Different HV :

Magnitude of n

VH1

Large HV implies ihai volume density of charge carriers is small //

Small HV implies that volume density of charge carriers is large.

Direction of HV perpendicular to the current in a conductor.

If direction of HV , is as shown in the above figure, it implies that charge

carriers are negatively charged // If direction of HV is in the opposite

direction, its implies that carriers are positively charged.

1M 1M 1M 1M

Total 15 M