2000 - WAEC Physics Past Questions and Answers - page 3
21
The mass of water vapour in a given volume of air is 0.05g at 20oC, while the mass of water vapour required to saturate it at the same temperature is 0.15g. Calculate the relative humidity of the air
A
3.33%
B
5.55%
C
33.33%
D
55.55%
correct option: c
Users' Answers & Comments22
The temperature at which the saturated vapour pressure of a liquid is equal to the external atmospheric pressure is known as its
A
dew point
B
boiling point
C
lower fixed point
D
tripple point
correct option: b
Users' Answers & Comments23
A periodic pulse travels a distance of 20.0m in 1.00s. If its frequency is 2.0 x 103Hz. Calculate the wavelength.
A
1.0 x 10-3m
B
1.0 x 10-2m
C
2.0 x 10-2m
D
1.0 x 102m
correct option: b
Users' Answers & Comments24
A wave has an amplitude equal to 4.0m, angular speed \(\frac{1}{3} \pi\) rads-1 and phase angle \(\frac{2}{3} \pi\) rad. The displacement y of the wave particle is given as
A
y = 4 sin \(\frac{\pi}{3}\)(t + 2)
B
y = 4 sin \(\frac{\pi}{3}\)(t + \(\frac{2}{\pi}\)
C
y = 4 sin \(\frac{\pi}{3} (2t + 1)\)
D
y = 4 sin \(\frac{\pi}{3} (t + 2)
correct option: c
Users' Answers & Comments25
In the diagram above, an incident ray AY makes an angle of 30o with the normal XY. If the mirror is rotated anticlockwise about Y through an angle of 20o, while AY is fixed, what angle will the reflected ray now make with the incident ray?
A
70o
B
80o
C
100o
D
120o
correct option: c
Users' Answers & Comments26
A concave mirror can be used to produce a parallel beam of light if a lighted bulb is placed
A
between its focus and the pole
B
at its focus
C
at its centre of curveture
D
between its focus and centre of curvature
correct option: b
Users' Answers & Comments27
A simple microscope forms an image 10cm from an eye close to the lens. If the object is 6cm from the eye, calculate the focal length of the lens
A
3.75cm
B
4.00cm
C
15.00cm
D
16.00cm
correct option: a
Users' Answers & Comments28
When white light passes through a triangular glass prism, there is dispersion because of
A
diffraction of light
B
polarisation of light
C
the difference in speed of the components of light
D
the interference of light waves in glass
correct option: c
Users' Answers & Comments29
In which of the following media does sound travel faster?
A
water
B
brass
C
air
D
wood
correct option: b
Users' Answers & Comments30
A turning fork of frequency 600Hz is sounded over a closed resonance tube. If the first and second resonant positions are 0.130m and 0.413m respectively, calculate the speed of sound in air
A
508.4ms-1
B
480.0ms-1
C
339.6ms-1
D
169.8ms-1
correct option: c
\(v = f\lambda\)
\(v = 2f \times (l_{2} - l_{1})\)
\(v = 2 \times 600 \times(0.413 - 0.130)\)
\(v = 1200 \times 0.283\)
\(v = 339.6ms^{-1}\)