Question Bank
Class-XI
WAVES
1. Which properties of a
medium are responsible for propagation of waves through it?
2. Which characteristics of the medium, determine
the velocity of longitudinal sound waves in a medium? How will velocity of
sound be affected at high altitude?
3. Can transverse waves be produced in air?
4. What type of waves is produced
on water surface?
5. Why cannot astronauts on the moon talk to
each other as on earth?
6. An explosion occurs
inside a lake. What type of waves is produced inside the water?
7. In which gas -H2 or O2 will
sound travel with greater speed under given conditions of temperature and
pressure?
8. How is energy
transmitted in wave motion?
9. Sound can be heard over
longer distance on a rainy day. Why?
10. The velocity of sound
is generally greater in solids than in gases at N.T.P Why?
11. Frequency is the most
fundamental property of a wave .Why?
12. What are the requisites
for the propagation of a wave through a medium? Define the terms transverse and
longitudinal wave motion.
13. Define Mach number.
What are –subsonic, supersonic and ultra-sonic waves?
14. Discuss the effect of
density and humidity on velocity of sound in air.
15. Explain the effect of
pressure and frequency on velocity of sound in air.
16. Discuss Newton’s
formula of velocity of sound in air point out the error and hence discuss Laplace
correction.
17. State Newton’s formula
for velocity of sound in gases. Discuss Laplace correction .What is the effect
of density, pressure and temperature on the velocity of sound in air? Explain.
18. Distinguish between
transverse and longitudinal waves .Also show that velocity of sound in air is
independent of pressure provided the temperature of medium remains constant.
19. Why are the stationary
waves called so?. Derive an expression for stationary wave.
20. Name the two
instruments based on superposition of waves.
21. The beats are not
heard, if the difference in frequencies of the sounding notes is more than 10.
Why?
22. Bats can ascertain
distances, directions, nature and size of the obstacles without any eyes.
Explain, Why.
23. A travelling wave in a
stretched string is described by the equation
Y=r sin (k x-w
t)
What is the maximum particle velocity?
24. Why a diver under water
is unable to hear the sound produced in air?
25. How does the frequency
of a tuning fork change, when the temperature is increased?
26. A tuning fork is in
resonance with a closed pipe. But the same tuning fork cannot be in resonance
with an open pipe of the same length. Why?
27. When we start filling
an empty bucket with water, the pitch of the sound produced goes on changing.
Why?
28. Tow organ pipes of same
length open at both ends produce sound of different frequencies, if their radii
are different. Why?
29. If oil of density
higher than of water is used in place of water in a resonance tube, how does
the frequency change?
30. Define phase velocity,
angular frequency and propagation constant. Obtain a relation between them.
31. What is a progressive
wave? Derive an expression, which represents progressive wave. Write down the
characteristics of progressive waves.
32. Draw the
diagram of the first two modes of transverse vibration of a stretched string
fixed at the ends and locates the positions of the antinodes and nodes.
33. What property of waves proves that night waves transverse?
How fundamental frequency of a transverse vibration string depends on- i)
radius of string. ii) Density of string.
34. Which property of the wave proves that sound
waves are longitudinal? Beats are not observed for light waves. Why?
35. A sound
wave travels from air to water. The angle of incidence at the surface of
separation between air and water is i1 and the angle of
refraction is i2. Snell’s law is applicable in this case.
Determine which of i1 and i2 bigger.
36 is. Why do
sound waves not undergo polarization?. Derive the relation between
wave-velocity, wave-length and frequency of a wave?
37. Are sound
waves travelling through a solid longitudinal or transverse?
38. Write down the relation
between the wave length, the frequency and the velocity of a sinusoidal wave.
39. Can you propagate
transverse waves in a liquid? Write down the laws of transverse vibrating string.
40. In case of a transverse
wave do the particles of the medium vibrate in a plane parallel to the plane of
propagation of the wave?
41. For a standing wave
what is the relation of the distance of separation between two consecutive
nodes with wavelength?
42. Define Doppler‘s
effect. What do you mean by apparent
frequency and Doppler shift?
43. All harmonics are
overtones, but all overtones are not harmonics-Explain
44. In a gaseous medium
longitudinal waves can propagate but a transverse wave cannot.-Explain with
reasons.
45. How much is the phase
difference between the following two progressive waves?
Y=A sin (wt-2πx) and Y=A Cos
(wt-2πx)
46. What are the conditions
for the clear audibility of beat? Derive an expression for beats. Write down
the applications of beats.
47. Why does the sound
emitted by an open pipe appear more musical than the sound emitted by a closed
pipe?
48. What are the principal
differences between light wave and sound wave?
49. What do you mean by
phase of a progressive wave?. How phase
difference of a progressive wave related to-i) path difference and ii) time
difference.
50. Define particle
velocity and wave velocity. Derive a relation between them. Write down the
differences between them.
51. Derive an expression
for particle velocity and particle acceleration of a progressive wave. What is
the phase differences between-i) particle velocity and particle acceleration
and ii) particle displacement and particle velocity?.
52. What is an echo? How is
it produced? Why is and echo not heard in a small room? What is reverberation
of sound?
53. Define- i) sonic boom
ii) RADAR. Show that in an isothermal process bulk modulus of gas is equal to
the pressure of the gas.
54. Show that in adiabatic
process bulk modulus of a gas is equal to the product of the ratio of two
specific heats of the gas and its pressure.
55. Why is the velocity of
sound in moist air greater than that in dry air at the same temperature?
Determine the relationship between the rms velocity of the molecules of a gas
and the velocity of sound in the gas.
56. Write down the
expressions for apparent frequencies in following cases-i) When an observer is
moving towards a stationary source of sound ii) When a observer is moving away
from a stationary source of sound iii) When a source is moving towards a
stationary observer iv) When a source is moving away from a stationary observer
v) When source and observer both are moving towards each other vi) When source
and observer both are moving away from each other?
57. How will you determine
the velocity of sound by resonance air column method? What is the
end-correction in this experiment? How velocity of sound depends on radius of
resonance tube?
58. Show that fundamental
frequency of an open organ pipe is one octave higher than the fundamental
frequency of a closed organ pipe of same length.
59. Explain-“Open organ
pipes are more musical than close organ pipes”
