### Physics - Waves

#### Question - 1

Choose the INCORRECT statement

• A Audibility range of a human ear is 20 Hz to 20 kHz
• B Linear distance between the successive points which are in the same phase is half of the length of a wave
• C The temperature at which velocity of sound in air is double its velocity at ${ 0 }^{ \circ }C$ is $819^{ \circ }C$
• D The velocity of sound increases with increase of humidity

#### Question - 2

Sound travels fastest in

• A hydrogen
• B vacuum
• C water
• D steel

#### Question - 3

Sound waves cannot be

• A refracted
• B polarised
• C scattered
• D used to produce hologram

#### Question - 4

In the formation of beats due to superposition of two wavetrains of nearly equal frequencies, the maximum loudness at the waxing is found to be k times the loudness of each component wavetrains. The value of k is

• A 1
• B 2
• C 4
• D 8

#### Question - 5

In the formation of beats

• A the amplitude of vibrations of the particles of the medium at any point executes simple harmonic motion which has frequency equal to the difference in the frequencies of the two waves.
• B the particles of the medium vibrate to and fro simple harmonically with the frequency equal to the difference in the frequencies of the two waves
• C the amplitude of vibrations of the particles of the medium executes simple harmonic motion which has frequency equal to half of the difference in the frequencies of the two waves
• D the amplitude of maxima and minima remains constant

#### Question - 6

Choose the CORRECT statement

• A Longitudinal waves are possible in solids, liquids and gases
• B Longitudinal waves are possible only in solids and liquids
• C Both transverse and longitudinal waves are possible in solids, liquids and gases
• D Transverse waves are not possible in vacuum

#### Question - 7

In the formation of stationary waves,

• A only nodes are in the same phase
• B the particles with an interval between two neighbouring intervals are of opposite phase
• C the phase difference along the direction of propagation increases as the distance from the source increase
• D the phase of motion of all particles of the medium is same

#### Question - 8

Choose the CORRECT statement

• A A progressive wave has a nods at the beginning
• B A transverse wave cannot be refracted
• C A progressive wave cannot be refracted
• D A transverse wave can be polarised

#### Question - 9

In a stationary waves,

• A the energy of the waves is zero
• B the energy in the medium is zero
• C the energy transfer in the direction of propagation is zero
• D the energy density of the waves is constant

#### Question - 10

A wave is reflected normally from the surface of a denser medium back into the rarer  medium. The phase of the wave caused by reflection will differ by

• A a quarter cycle
• B a half cycle
• C a cycle
• D a three-fourth of a cycle