2002 - WAEC Physics Past Questions and Answers - page 3
21
Calculate the energy required to vapourise 50g of water initially at 80oC.[specific heat capacity of water = 2260Jg-1K-1][specific latent heat of vaporisation of water = 2260Jg-1]
A
113,000J
B
117,200J
C
234,400J
D
420,000J
22
What type of motion does the skin of a 'talking' drum perform when it is struck with a drum stick?
A
Random
B
Rational
C
Translational
D
vibratory
correct option: d
Users' Answers & Comments23
A slinky spring fixed at one end is placed horizontally on a table. The free end is displaced parallel to the table and then released. The resultimg wavelength is
A
transverse
B
longitudinal
C
stationary
D
electromagnetic
correct option: b
Users' Answers & Comments24
A radio wave has a wavelength of 150m. If the velocity of radio waves is free spaces is 3 x 10\(^8\) ms\(^{-1}\), calculate the frequency of the radio wave
A
4.50 x 1010Hz
B
5.0 x 109Hz
C
4.5 x 109Hz
D
2.0 x 106Hz
correct option: d
f = \(\frac{V}{\lambda} = \frac{3 \times 10^8}{150}\)
= 2.0 x 10\(^6\) Hz
25
In the wave equation y = Eo, sin(299t - \(\pi\)), Eo represents the
A
amplitude
B
frequency
C
period
D
wavelength
correct option: a
Users' Answers & Comments26
The size of the hole of a pin hole camera is increased. The resultant image formed becomes
A
sharper
B
reduced in size
C
enlarged
D
blurred
correct option: d
Users' Answers & Comments27
The refractive index of a medium relative to air is 1.8. Calculate to the nearest degree, the critical angle for the medium
A
68o
B
56o
C
34o
D
18o
correct option: c
c = \(\sin^{-1} \frac{1}{n} = \sin^{-1} \frac{1}{1.8} = 34^o\)
Users' Answers & Comments28
A converging lens of focal length 15cm forms a virtual image at a point 10cm from the lens. Calculate the distance of the object from the lens
A
10.00cm
B
6.00cm
C
5.00cm
D
1.50cm
correct option: b
\(\frac{1}{u} + \frac{1}{v} = \frac{1}{f} = \frac{1}{15} + \frac{1}{10}\)
u = 6.00
Users' Answers & Commentsu = 6.00
29
In a compound microscope, the image formed by the objective lens is at a distance of 3.0cm from the eye lens. Calculate the focal length of the eye lens
A
0.3cm
B
2.7cm
C
3.4cm
D
8.3cm
correct option: c
\(\frac{1}{f} = \frac{1}{u} + \frac{1}{v} = \frac{1}{3} - \frac{1}{25} = \frac{22}{75}\)
f = 3.4cm
Users' Answers & Commentsf = 3.4cm
30
A pulse of a sound is transmitted from a ship and the reflection from the sea bed is recorded after 0.2s. Calculate the depth of the sea. [Take speed of sound in sea water = 1560ms-1]
A
312.0m
B
156.0m
C
78.0m
D
31.2m