# 2015 - JAMB Physics Past Questions & Answers - page 1

1
The direction of the path taken by light is called
A
Locus
B
Lines
C
Ray
D
Beam
CORRECT OPTION: c
Ray – a beam of light or radiation
2
What is the inductance (L) of an inductor whose reactance is 1Ω at 50/ π hertz (H)?
A
100 H
B
0.01H
C
10H
D
1H
CORRECT OPTION: b
XL = WL = 2πFL (w = 2πf)

XL = reactance inductor (S.I unit Ω)

L = inductance (L) in Henry

XL = 1Ω, f = 50/π, L = ?

1 = 2× π × 50/π × L

1 = 100L

i.e. 100L = 1

L = 1/100

0.01H

∴ Inductance (L) of a inductor = 0.01H
3
A stroboscope can be used to make the ware appear …………..
A
Stationary
B
In motion
C
Dipper
D
Ripple
CORRECT OPTION: a
Stroboscope is a scientific instrument used to make a wave appears stationary when used
4
In an elastic collision

I. Energy is conversed
II. Energy is decreased
III. Energy is increased
IV. Linear momentum conversed
A
I only
B
II and IV only
C
II only
D
III only
CORRECT OPTION: b
In an inelastic collision, linear momentum is conserved and energy is decreased

Momentum and kinetic energy are conserved in elastic collision
5
Body floats in fluid when its …………………
A
Displaces its own volume of the liquid (fluid)
B
Displaces its own mass of the fluid
C
Displace its own density of the fluid
D
Is no longer subjected to gravity
CORRECT OPTION: b
Note:The principle of floatation states that a floating body displaces its own weight of the fluid or which its float.

For object to sink weight of the object (W) > upthrust of the fluid (v) i.e. w > u

(i.e. weight of the body (or object) mass of the fluid)
6
The general gas law can be written as
A
PV ÷ T = a constant
B
PV = a constant
C
v/t = a constant
D
p/T = a constant
CORRECT OPTION: a
Formula for general gas law

V × 1/T × P

N [(PV) ÷ T] = K is constant
7
A motor boy of a driver saw what seem to appear to be a pool of water a head of him, while his driver’s drives a new truck on a funny day. Which of the following explains his observation?
A
He saw a flying objects
B
He must be thinking of water and food
C
He was seeing the shadow of the car
D
The sun ray from the sky were passing from a hot air (layer) to cold layer
CORRECT OPTION: d
The appearance of pool of water on road surfaces is called MIRAGE

His observation show that light from the sun ray refracted through a layer of hot air(layer) which is closed to the ground, passes from a hot air layer to the cold layer
8
Which of the following is not luminous object?
A
The sun
B
The moon
C
light candle
D
Star
CORRECT OPTION: b
Sun are self luminous source
Moon is a non – luminous
9
The resultant force of a couple is ………?
A
Infinity
B
Zero
C
One
D
Half
CORRECT OPTION: b
Note: moment of a couple = force × length (fL)

The tangential force is actingin an opposite direction alongside its length

i.e f1 L1 = f2L2

f2L2 − f1 L1 = 0(i.e Zero)
10
A vector quantity can only be completely described when ……… and …………are mentioned.
A
Magnitude and motion
B
Magnitude and direction
C
Distance and specified displacement
D
Moment and momentum
CORRECT OPTION: b
A vector quantity has both magnitude and direction
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