1.The ratio of densities of nitrogen and oxygen is
14:16. The temperature at which the speed of
sound in nitrogen will be same at that in oxygen
at 55°C is
a) 35°C
b) 48°C
c) 65°C
d) 14°C
Explanation:
2. The intensity of sound increases at night due to
a) Increase in density of air
b) Decreases in density of air
c) Low temperature
d) None of these
Explanation: We know that at night amount of carbon dioxide in atmosphere increases which raises the density of atmosphere. Since intensity is directly proportional to density, intensity of sound is more at night
3.A wavelength 0.60 cm is produced in air and it
travels at a speed of 300 m \[s^{-1}\] . It will be an
a) Audible wave
b) Infrasonic wave
c) Ultrasonic wave
d) None of the above
Explanation:
4. Speed of sound in mercury at a certain
temperature is 1450 m/s. Given the density of
mercury as \[13.6\times 10^{3} kg / m^{3}\] , the bulk modulus
for mercury is
a) \[2.86\times 10^{10} N / m^{3}\]
b) \[3.86\times 10^{10} N / m^{3}\]
c) \[4.86\times 10^{10} N / m^{3}\]
d) \[5.86\times 10^{10} N / m^{3}\]
Explanation:
5. A micro-wave and an ultrasonic sound wave have
the same wavelength. Their frequencies are in the
ratio (approximately)
a)\[10^{6} : 1\]
b) \[10^{4} : 1\]
c) \[10^{2} : 1\]
d) 10 :1
Explanation:
6. A point source emits sound equally in all
directions in a non-absorbing medium, Two points
P and Q are at distance of 2m and 3m respectively
from the source. The ratio of the intensities of the
waves at P and Q is
a) 9 : 4
b) 2 : 3
c) 3 : 2
d) 4 : 9
Explanation:
7. A wave has velocity u in medium P and velocity 2u
in medium Q. If the wave is incident in medium P
at an angle of 30° then the angle of refraction will
be
a)30°
b) 45°
c) 60°
d) 90°
Explanation:
8.An observer standing near the sea shore observes
54 waves per minute. If the wavelength of the
water wave is 10m then the velocity of water
wave is
a) 540 m \[s^{-1}\]
b) 5.4 m \[s^{-1}\]
c) 0.184 m \[s^{-1}\]
d) 9 m \[s^{-1}\]
Explanation:
9. Ultrasonic signal sent from SONAR returns to it
after reflection from a rock after a lapse of 1 sec.
If the velocity of ultrasound in water is 1600 m \[s^{-1}\] ,
the depth of the rock in water is
a) 300 m
b) 400 m
c) 500 m
d) 800 m
Explanation:
10.The equation of a wave is \[y=2\sin \pi\left(0.5 x-200 t\right)\] ,
where x and y are expressed in cm and t in sec.
The wave velocity is
a) 100 cm/sec
b) 200 cm/sec
c) 300 cm/sec
d) 400 cm/sec
Explanation:
