Tag: propagation of sound waves

Questions Related to propagation of sound waves

Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen. This is because:

physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

  1. speed ofsound is greater than speed oflight

  2. speed of sound is equal to the speed of light

  3. speed of light is much greater than the speed of sound

  4. none of these

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Correct Option: C
Explanation:

It is because light travels faster  ($3\times10^{8}m/s$) than sound ($332m/s$) , so we hear thunder after a few second of the flash .

Correct comparison between light waves and sound waves is:

physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

  1. Both are mechanical waves

  2. Both need a material medium for propagation

  3. Both can travel through vacuum

  4. None

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Correct Option: D
Explanation:

Sound waves are mechanical waves, light waves are electromagnetic waves. Light can travel through vacuum, sound cannot.

Sound waves travels _________ than light in vacuum.

physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

  1. faster

  2. slower

  3. not slower

  4. Can't travel

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Correct Option: D
Explanation:

Light waves are non mechanical waves. They don't need a material medium for their propagation. So they can travel through vacuum. But sound waves can't travel through vacuum.

Sound waves travels _____  light in air

physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

  1. faster than

  2. slower than

  3. at same speed as

  4. either faster than or with same speed as

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Correct Option: B
Explanation:

Light waves are non mechanical waves. Speed of non mechanical waves is much higher than mechanical waves.

The distance between tow adjacent particles which are in the same phase in a progressive wave is 20 cm. determine the velocity of the wave if its frequency is 10 Hz.

physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

  1. $2 {ms}^{-1}$

  2. $40 {ms}^{-1}$

  3. $8 {ms}^{-1}$

  4. $80 {ms}^{-1}$

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Correct Option: A

Light and Sound waves

physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

  1. both are mechanical waves

  2. both need material media for propagation

  3. both can travel through vacuum

  4. are two different types of waves

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Correct Option: D
Explanation:

Sound waves are mechanical waves which are longitudinal in nature and require material media to pass through.

Light waves are electromagnetic waves which are transverse in nature and do not require any material medium to pass through.

The thunder of a cloud is heard later compared to flash of lightning because :

physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

  1. speed of sound is greater than speed of light

  2. speed of light is greater than speed of sound

  3. speed of sound is the same as speed of light

  4. sound is obscured by the rain

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Correct Option: A
Explanation:

The light travels much faster than the sound. The thunder travels at the speed of sound while the light from the flash travels at the speed of the light. The speed of light is about 340 m/s through air, while the speed of light is about 300 million m/s.So the thunder is heard after the flash of lightening.

You see lightning before you hear the thunder because

physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

  1. Lightning is much brighter than thunder.

  2. Thunder is heavier than lightning.

  3. Light can travel through air but sound cannot.

  4. Sound travels slower than light.

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Correct Option: D
Explanation:

Answer is D.

Lightning and thunder are produced simultaneously, but the thunder is heard a few seconds after the lightning is seen. This is because the speed of light in air is more than the speed of sound in air.The speed of light is given as $3\times { 10 }^{ 8 }m/s$. The speed of sound is 340 m/s.
Hence, the flash of lightning is seen before the thunder is heard as the speed of sound is less than speed of light.

Speed of sound wave in a gas is $v _{1}$ and tins speed of molecules of the gas at the same temperature is $v _{2}$. Then :

physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

  1. $ v _{1} = v _{2}$

  2. $ v _{1} < v _{2}$

  3. $ v _{1} > v _{2}$

  4. $v _{1}\le\ v _{2}$

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Correct Option: A

A source of frequency 500Hz emits waves of wavelength 0.2m.How long does it take to travel 300 m?

physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

  1. 70 s

  2. 60 s

  3. 12 s

  4. 3 s.

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Correct Option: D