2016 - WAEC Physics Past Questions and Answers - page 3
21
Which of the following statements is correct about the effect of dissolved salt on the freezing point of water?
A
the freezing point is lowered
B
the freezing point is increased
C
there is no change in the freezing point
D
the change in the freezing point depends on the temperature of the surrounding
correct option: a
Users' Answers & Comments22
A pressurized perfume bottle is left on the window pane of a room. What happens to he gas molecules of the perfume on a sunny day? They
A
expand
B
collide less often
C
move more rapidly
D
contract
correct option: c
Users' Answers & Comments23
Given that v, f and \(\lambda\) are the velocity, frequency and wavelength of a wave respectively. Which of the following equations is correct?
A
v = f2\(\lambda\)
B
f = \(\frac{v}{\lambda}\)
C
f = \(\frac{v}{\lambda^2}\)
D
\(\lambda = \frac{f}{v^2}\)
correct option: b
Users' Answers & Comments24
The distance between two successive trough of a wave is 0.4m. If the frequency of the source is 825Hz, Calculate the speed of the wave
A
165.0 ms-1
B
330.0ms-1
C
41.5ms-1
D
85.0ms-1
25
X-rays and infrared rays are both electromagnetic. Which common property do the waves have? Both waves
A
are longitudinal
B
have same frequency
C
have the same wavelength
D
travel at the same speed in a vacuum
correct option: d
Users' Answers & Comments26
The image formed by a concave mirror is real, inverted and magnified, when object is placed
A
at the focus
B
at the centre of curvature
C
beyond the centre of curvature
D
between the centre of curvature and the focus
correct option: d
Users' Answers & Comments27
Total internal reflection. i. is a phenomenon of refraction of light. ii. occurs when light rays travel into a denser medium. iii. occurs when the critical angle is just exceeded. iv. is a phenomenon of reflection of light. Which of the statements above are correct?
A
i and ii only
B
i and iii only
C
i, ii and iii only
D
i, iii and iv only
correct option: b
Users' Answers & Comments28
Complementary colours are those which
A
have the same refractive index
B
have the same wavelength
C
add-up to produce black light
D
add-up to produce white light
correct option: d
Users' Answers & Comments29
The diagram given illustrates the waveform of a note produced by vibrations in an air column of length L. If the speed of sound in air is V, derive an expression for the frequency of the notes
A
\(\frac{V}{L}\)
B
\(\frac{5VL}{2}\)
C
\(\frac{5L}{4V}\)
D
\(\frac{5V}{4L}\)
correct option: d
L = \(\frac{5\lambda}{4}\)
\(\lambda = \frac{4L}{5}\)
But \(\lambda = f\lambda\)
f = \(\frac{v}{\lambda} = \frac{v}{\frac{4L}{5}}\)
= \(\frac{5v}{4L}\)
Users' Answers & Comments\(\lambda = \frac{4L}{5}\)
But \(\lambda = f\lambda\)
f = \(\frac{v}{\lambda} = \frac{v}{\frac{4L}{5}}\)
= \(\frac{5v}{4L}\)
30
The pair of musical instruments that works on the vibration of air in pipes is
A
piano and the organ
B
guitar and the flute
C
trumpet and the violin
D
flute and the trumpet
correct option: d
Users' Answers & Comments