2012 - JAMB Physics Past Questions and Answers - page 4
31
Disperson of white light is the ability of white light to
A
penetrate air, water and glass
B
move in a straight line
C
move around corners
D
separate to its component colours
correct option: d
Users' Answers & Comments32
A newly charged 12V accumulator can easily start a car whereas eight new dry cells in series with a effective e.m.f. of 12V cannot start the same car because
A
The current capacity is high
B
The current capacity is low
C
it cannot be re-charged
D
it cannot easily be connected to a car
correct option: b
Users' Answers & Comments33
The fuse in an electric device is always connected to the
A
neutral side of an electric supply
B
earth side of an electric supply
C
live side of an electric supply
D
terminal side of an electric supply
correct option: c
Users' Answers & Comments34
A particle carrying a charge of 1. 0 x 10-8C enters a magnetic field at 3.0x 10-2 ms -1 at right angles to the field. If the force on this particle is 1.8 x 10-8N, what is the magnitude of the field?
A
6.0x10-1T
B
6.0x10T
C
6.0x10-3T
D
6.0x10-4T
correct option: b
F = BQV
B = \(\frac{F}{QV}\)
B = \(\frac{1.8 \times 10^{-8}}{1.0 \times 10^{-8} \times 3.0 \times 10^{-2}}\)
Users' Answers & CommentsB = \(\frac{F}{QV}\)
B = \(\frac{1.8 \times 10^{-8}}{1.0 \times 10^{-8} \times 3.0 \times 10^{-2}}\)
35
The current output from of an a.c. source is given as I = 10 sin to t. The d.c equivalent of the current is
A
5.0A
B
7.1A
C
10.0A
D
14.1A
36
A conductor of length 1m moves with a velocity of 50ms-1 at an angle of 30o to the direction of a uniform magnetic field of flux density 1.5Wbm-2. What is the e.m.f induced in the conductor?
A
37.5V
B
50.5V
C
75.0V
D
80.5V
correct option: a
Users' Answers & Comments37
The process of detecting a pin mistakenly swallowed by a child is X-ray
A
Diagnosis
B
Therapy
C
Crystallography
D
Mammography
correct option: c
Users' Answers & Comments38
Which of the following particies CANNOT be deflected by both electric and magnetic fields?
A
Gamma rays
B
Alpha particles
C
Wave particles
D
Beta particles
correct option: a
Users' Answers & Comments39
A piece of radioactive material contains 1000 atmos. If its half -life is 20seconds, the time taken for 125 atoms to remain is
A
20 seconds
B
40 seconds
C
80 seconds
D
60 seconds
40
The p-n junction diodes can act as rectifiers because they
A
conduct current when forward-biased
B
conduct current when reverse-biased
C
block current when forward-biased
D
conduct current in both directions
correct option: b
Users' Answers & Comments