# 2011 - WAEC Physics Past Questions and Answers - page 1

1
Which of the following statements is not correct?
A
molecules of ice, water and water vapour have equal intermolecular distances
B
molecules of ice, water and water vapour do not differ in the structure of their molecules
C
molecules of water vapour attract each other with forces far less than the forces of attraction between water molecules
D
water is less compressible than water vapour
correct option: a
2
The density P of a spherical ball of diameter d and mass m is given by
A
P = $$\frac{3m}{4 \pi d^3}$$
B
p = 4$$\pi md^3$$
C
p = $$\frac{6m}{\pi d^3}$$
D
p = $$\frac{3m}{2 \pi d^3}$$
correct option: c
p = $$\frac{M}{V} = \frac{M}{\frac{4}{3} \pi (\frac{d}{\pi})^3}$$

= $$\frac{6m}{\pi d^3}$$
3
A metal rod of density 7000 kgm-3 and cross-sectional area of 0.001257m2 has a mass of 1.76kg. Calculate its length.
A
0.20m
B
0.25m
C
0.40m
D
0.50m
correct option: a
P = $$\frac{M}{AL}$$

L = $$\frac{M}{CA}$$

= $$\frac{1.76}{7000 \times 0.001257}$$

= 0.2m
4
The pressure in a liquid
A
is the same at all points in the liquid
B
decreases with depth
C
is the same in all directions at a given point
D
is equal to the atmospheric pressure
correct option: c
5
The property of a fluid that is used to determine its suitability as a lubricant is its
A
capillarity
B
viscocity
C
surface tension
D
relative density
correct option: b
6
The area under a velocity-time graph represents
A
final velocity attained
B
distance covered
C
acceleration
D
workdone
correct option: b
7
In the absence of gravitational force, the weight of the body is
A
its mass
B
zero
C
its density
D
its volume
correct option: b
8
Which of the following propeties is not considered in choosing mercury as a thermomemetric liquid?
A
density
B
expansivity
C
conductivity
D
opacity
correct option: a
9
A stone of mass 300g is released from rest from the top of a bulding of height 100m. Determine the kinetic energy gained by the stone when it is a quarter way down from the point of release.[g = 10 ms-2]
A
750.0J
B
225.0J
C
75.0J
D
22.5J
correct option: c
K.E = P.E = mgh

= 0.3 x 10 x 100 - 0.3 x 10 x 75

= 75J
10
A body of mass 120g placed at the 10cm mark on a uniform metre rule makes the rule settle horizontally on a fulcrum places at 35cm mark. Calculate the mass of the rule
A
60g
B
80g
C
120g
D
200g
correct option: d
m = $$\frac{25 \times 120}{15}$$

= 200g