# 2004 - WAEC Physics Past Questions and Answers - page 1

1
The molecular structure of a liquid is such that
A
the molecules have unlimited freedom of movement
B
molecular movement is restricted to vibration only
C
intermolecular collisions take place
D
all molecules moves move with the same speed
correct option: c
2
Which of the following statements about the mass and the weight of a body is not correct? its
A
mass is a scalar quantity
B
weight is a function of the gravitational pull on it
C
mass on earth and on the moon is the same
D
weigh at the equatior and at the poles is the same
correct option: d
3
An object weighs 60.0N in air, 48.2N in a certain liquid X, and 44.9N in water, Calculate the relative density of X
A
3.300
B
1.279
C
0.932
D
0.782
correct option: d
R.d = Wt in Air-Wt in Air-Wt in water

= $$\frac{60.0 - 48.2}{60.0 - 44.9}$$

= 0.782
4
Calculate the change in volume when 90g of ice is completely melted. [density of water = 1g cm-3, density of ice = 0.9cm-3]
A
0.00cm3
B
9.00cm3
C
10.00cm3
D
90.00cm3
correct option: c
$$\Delta$$y = Vice - Vwater

= $$\frac{90}{0.9} - \frac{90}{1} = 10cm^3$$
5
The diagram above represent displacement D, versus time, t graph of a progressive wave. Deduce the frequency of the wave
A
20 Hz
B
10 Hz
C
5 Hz
D
4 Hz
correct option: b
6
Which of the following concept is not an evidence of the particle nature of matter?
A
diffusion
B
brownian motion
C
diffraction
D
crystallization
correct option: d
7
A diver is 5.2m below the surface of water of density 1000Kgm-3. If the atmospheric pressure is 1.02 x 105pa. Calculate the pressure on the diver [g = 10ms-2]
A
6.20 x 104 pa
B
1.02 x 105 pa
C
1.54 x 105 pa
D
5.20 x 105 pa
correct option: c
P = hpg + A.P

= 5.2 x 1000 x 10 + 1.02 x 105

= 1.54 x 105
8
A steel needle floating on water, sinks when kerosine is added to the water. This is because the kerosine
A
increased the surface tension of the water
B
reduces the density of the water
C
reduces the surface tension of the water
D
reduces the upthrust on the needle
correct option: c
9
On which of the following factor does the viscosity of a liquid depend? i. Nature of the liquid. ii. Temperature of the liquid. iii. Area of the liquid surface
A
i and ii only
B
ii and iii only
C
i and iii only
D
i, ii and iii
correct option: d
10
An elastic string of force constant 200N m-1 is stretched through 0.8m within its elastic limit. Calculate the energy stored in the string
A
64.0J
B
80.0J
C
128.0J
D
160.0J
correct option: a
E = $$\frac{1}{2}Ke^2$$

= $$\frac{1}{2} \times 200(0.8)^2 = 64J$$