2002 - JAMB Physics Past Questions and Answers - page 5
41
The particle that is responsible for the nuclear fission in a nuclear reactor is
A
neutron
B
prton
C
electron
D
photon
correct option: a
In a nuclear reaction, neutron is used as a bullet fired into 23592U, to trigger off nuclear chain reaction, which of course is controlled
Users' Answers & Comments42
A transistor is used in the amplification of signals because it
A
controls the flow of current
B
consumes a lot of power
C
allows doping
D
contains electron and hole carriers
correct option: a
Users' Answers & Comments43
The carbon-granules microphone works on the principle of change in
A
inductance
B
resistance
C
capacitance
D
voltage
correct option: b
Users' Answers & Comments44
At what frequency would a capacitor of 2.5μF
used in radio circuit have a resistance of 250Ω
used in radio circuit have a resistance of 250Ω
A
π/800 Hz
B
800/π Hz
C
200π Hz
D
2000π Hz
correct option: b
| Capacitive Reactance = | ___1 |
| 2π + C |
| => 250 = | ____1 |
| 2 x π x f x 2.5 x 106 |
∴ 250/1 = 106/5.0xf
| => F = | ___106 |
| 250 x 5.0 x π |
| = | 106 |
| 1250π |
800/π
45
A current of 0.5 A flowing 3h Deposits 2g of metal during electrolysis. The quantity of the same metal that would be deposited by the currents of 1.5A flowing in 1h is
A
2g
B
6g
C
10g
D
18g
correct option: a
From Faradays Law, mass deposited during electrolysis is given by
M = ItZ
=> Z = M/(It)
For a current of 1.5A flowing for 1h, the mass M, deposited is given by
M= ZiT
= 2 / (0.5x3x60x60) x 0.5x1x60x60 / 1
= 2.0g
M = 2.0g
Users' Answers & CommentsM = ItZ
=> Z = M/(It)
| = | __2 |
| 0.5x3x60x60 |
For a current of 1.5A flowing for 1h, the mass M, deposited is given by
M= ZiT
= 2 / (0.5x3x60x60) x 0.5x1x60x60 / 1
= 2.0g
M = 2.0g
46
Which of the following statements is true of the properties of a moving coil galvanometer?
A
THe coil has a small area
B
There are strong hair springs to gives a large control panlel
C
There is a strong permanent magnet to give high magnetic flux
D
it has a small number of turns of coil
correct option: c
Users' Answers & Comments47
A bead travelling on a straight line wire is brought to rest at 0.2 by friction. IF the ,mass of the bead is 0.01kg and the coefficient of friction between the bead and the wire is 0.1, determine the work one by the friction
[g = 10ms2
[g = 10ms2
A
2 x 10-4
B
2 x 10-3
C
2 x 101
D
2 x 102
correct option: b
Work done by friction = Friction force x displacement from the relation, f = μR
where μ = coefficient of friction ; R = normal reaction
=> F = μ mg (r = mg)
= 0.01 x 0.01 x 10
∴ work done = F x displacement
= 0.1 x 0.01 x 10 x 0.02
= 0.002
= 2 x 10-3
Users' Answers & Commentswhere μ = coefficient of friction ; R = normal reaction
=> F = μ mg (r = mg)
= 0.01 x 0.01 x 10
∴ work done = F x displacement
= 0.1 x 0.01 x 10 x 0.02
= 0.002
= 2 x 10-3
48
If the total force acting on a particle is zero, the linear momentum will
A
Increase
B
Decrease
C
Be Constant
D
Increase then decrease
correct option: c
Users' Answers & Comments49
The colours seen on soap bubbles are due to
A
Diffraction
B
Refraction
C
Dispersion
D
Interference
correct option: d
Users' Answers & Comments