2015 - WAEC Physics Past Questions and Answers - page 3
21
In an experiment in which a molten substance is allowed to cool, the cooling curve above was obtained. The temperature 60oC is known as the
A
vaporization point
B
cooling temperature
C
boiling point
D
melting point
correct option: d
Users' Answers & Comments22
Which of the following concepts is a method of heat transfer that does not require a material medium?
A
conduction
B
radiation
C
diffusion
D
convection
correct option: b
Users' Answers & Comments23
Which of the following units is the S.I. unit of heat capacity?
A
Jkg-1
B
Jkg-1 K-1
C
JK-1
D
Jg-1K-1
correct option: c
Heat capacity = \(\frac{\text{Heat energy supplied}}{\text{Rise in temperature}}\)
= JK\(^{-1}\)
24
The pressure applied to an enclosed fluid to one end id transmitted equally throughout the fluid and to the container walls. This statement is
A
Archimede's principle
B
Bernoulli's principle
C
Pascal's principle Heisenberg's
D
Heisenberg's uncertainty principle
correct option: c
Users' Answers & Comments25
The diagram given illustrates a wave form. Determine the speed of the wave
A
5.4 ms-1
B
8.4 ms-1
C
9.6 ms-1
D
10.0 ms-1
correct option: d
Users' Answers & Comments26
What type of wave is emitted by a loud speaker?
A
Transverse
B
Longitudinal
C
Gamma
D
Radio
correct option: b
Users' Answers & Comments27
An object is placed 15cm from a diverging lens of focal length 12cm. The image of the object formed by the lens in
A
real and 6.67cm from the lens
B
virtual and 6.67cm from the lens
C
real and 60.00cm from the lens
D
virtual and 60.00cm from the lens
correct option: b
The focal length of a diverging lens is negative.
f = -12 cm; u = 15 cm.
\(f = \frac{uv}{u + v}\)
\(-12 = \frac{15v}{15 + v}\)
\(-12 (15 + v) = 15v \implies -180 - 12v = 15v\)
\(-180 = 15v + 12v \implies -180 = 27v\)
\(v = \frac{-180}{27} = -6.67 cm\)
The image is virtual and 6.67 cm from the lens.
28
A swimming pool is .1m deep. If it contains water of refractive index 1.3, calculate the apparent depth of pool
A
3.4m
B
2.7m
C
1.6m
D
0.8m
correct option: c
n = \(\frac{\text{real depth}}{\text{apparent depth}}\)
1.3 = \(\frac{2.1}{\text{apparent}}\)
A.D = \(\frac{2.1}{1.3} = 1.6\)
Users' Answers & Comments1.3 = \(\frac{2.1}{\text{apparent}}\)
A.D = \(\frac{2.1}{1.3} = 1.6\)
29
When an air column is set into vibrations, the distance between two consecutive nodes of the resultant wave is
A
one quarter of the wavelength
B
half of the wavelength
C
the wavelength
D
twice the wavelength
correct option: b
Users' Answers & Comments30
A girl standing some distance from the cliff claps her hands and hears the echo 0.8s later. calculate her distance from the cliff. [speed of sound in air = 320 ms-1]
A
23m
B
128m
C
288m
D
298m
correct option: b
V = \(\frac{2nx}{E}\)
= \(\frac{2 \times 1 \times X}{0.8} = 320\)
2x = 0.8 x 320
x = \(\frac{0.8 \times 320}{2}\)
= 128m
Users' Answers & Comments= \(\frac{2 \times 1 \times X}{0.8} = 320\)
2x = 0.8 x 320
x = \(\frac{0.8 \times 320}{2}\)
= 128m