1990 - WAEC Physics Past Questions and Answers - page 4
31
A parallel beam of light is to be obtained from the headlamp ofa car. At which of the following positions should the source of light be placed from the pole of its spherical minor?
A
At the focal point
B
At the centre of curvature
C
Beyond the centre of curvature
D
Between the focal point and the pole
correct option: a
Users' Answers & Comments32
The diagram above shows an incident ray A, inclined at angle of 50o to the interface CB. The ray OB is found to lie along the surface. What is the refractive index of the medium X with respect to air?
A
sin50o/sin40o
B
sin40osin50o
C
sin90o/sin50o
D
sin40o/sin90o
correct option: e
Users' Answers & Comments33
The diagram above shows an incident ray A, inclined at angle of 50o to the interface CB. The ray OB is found to lie along the surface. What is the refractive index of the medium X with respect to air?
A
sin50o/sin40o
B
sin40osin50o
C
sin90o/sin50o
D
sin40o/sin90o
correct option: e
Users' Answers & Comments34
The eye defect illustrated by the diagram above is
A
astigmatism
B
long sightedness
C
loss accommodation
D
short sightedness
correct option: b
Users' Answers & Comments35
The eye defect illustrated by the diagram above is
A
astigmatism
B
long sightedness
C
loss accommodation
D
short sightedness
correct option: b
Users' Answers & Comments36
A simple microscope forms an image twice the size of the object. If the focal length of the lens of the microscope is 20m, how far is the object from the lens?
A
10m
B
20m
C
30m
D
40m
correct option: c
Users' Answers & Comments37
Which of the following pairs of light rays shows the widest separation in the spectrum of white light?
A
Yellow and red
B
Orange and green
C
Violet and blue
D
Blue and green
correct option: e
Users' Answers & Comments38
Given that the gravitational constant is 7 X 10-11 Nm2kg-2, what is the force of attraction between 106kg mass of lead hanging one metre away from a 103kg mass of iron?
A
7 x10-20N
B
7 x 10-5N
C
7x10-2N
D
7x103N
39
Calculate the current in the 3Ω resistor shown in
the diagram above.
the diagram above.
A
3.0A
B
4.0A
C
4.3A
D
12.0A
correct option: b
Total Resistance R = 1/R = 1/R1 + 1/R2 + 1/R3
R = 12/13Ω
V = IR = (12/13) x 13 = 12v
1 across 3Ω = V/R = 12/3 = 4A
Users' Answers & CommentsR = 12/13Ω
V = IR = (12/13) x 13 = 12v
1 across 3Ω = V/R = 12/3 = 4A
40
What is the electric potential energy between two protons each of charge q and at a distance of r apart? (Permittivity of free space = εo)
A
4πεoq2r
B
qr/4πεo
C
q/4πεor
D
q2/4πεor
correct option: c
Users' Answers & Comments