Comparison of speed of sound with speed of light - class-X
comparison of speed of sound with speed of light
Questions
Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen. This is because:
- speed ofsound is greater than speed oflight
- speed of sound is equal to the speed of light
- speed of light is much greater than the speed of sound
- none of these
Correct comparison between light waves and sound waves is:
- Both are mechanical waves
- Both need a material medium for propagation
- Both can travel through vacuum
- None
Sound waves travels _________ than light in vacuum.
- faster
- slower
- not slower
- Can't travel
Sound waves travels _____ light in air
- faster than
- slower than
- at same speed as
- either faster than or with same speed as
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.
- $2 {ms}^{-1}$
- $40 {ms}^{-1}$
- $8 {ms}^{-1}$
- $80 {ms}^{-1}$
Light and Sound waves
- both are mechanical waves
- both need material media for propagation
- both can travel through vacuum
- are two different types of waves
The thunder of a cloud is heard later compared to flash of lightning because :
- speed of sound is greater than speed of light
- speed of light is greater than speed of sound
- speed of sound is the same as speed of light
- sound is obscured by the rain
You see lightning before you hear the thunder because
- Lightning is much brighter than thunder.
- Thunder is heavier than lightning.
- Light can travel through air but sound cannot.
- Sound travels slower than light.
Flash and thunder are produced simultaneously. But the thunder is heard a few seconds after the flash is seen. Why?
- The speed of sound is greater than the speed of light.
- The speed of sound is equal to the speed of light.
- The speed of light is greater than the speed of sound.
- The speed of light is less than the speed of sound.
The speed of light in vaccum is....
- $3 \times {10^8}m/s$
- $0.3 \times {10^8}m/s$
- $9 \times {10^8}m/s$
- $30 \times {10^8}m/s$
An observer measures speed of light to be C when he is stationary with respect to the source. If the observer moves with velocity $\displaystyle v$ towards the source then the velocity of light observed will be :
- $\displaystyle c- v$
- $\displaystyle c + v$
- $\displaystyle \sqrt{1-v^2/c^2}$
- $\displaystyle c$
Which of the following product of $e, h, \mu, G$ (where $\mu$ is the permeability) be taken so that the dimensions of the product are same as that of the speed of light?
- $h e^{-2} \mu^{-1} G^0$
- $h^2 e G^0 \mu$
- $h^0 e^2 G^{-1} \mu$
- $h G e^{-2} \mu^{0}$
The ratio of speed of ultrasonic wave and sound wave is:
- $=1$
- $>1$
- $<1$
- $>1$
A laser signal sent towards the moon returns after T seconds.If c is the speed of light, then the distance of the moon from the observer is given by
- cT
- $c{T^{ - 2}}$
- $\frac{{ct}}{2}$
- 2 cT
The speed of sound is $330 ms^{-1}$ and that of light is $3\times 10^8 ms^{-1}$. The ratio of speed of sound to that of light is approximately $1 : 10^6$.
- True
- False
Light .......... travel in vacuum , but the sound ........ travel in vacuum.
- Cannot , can
- Can, cannot
- Sometimes, never
- Never, sometimes
Speed of light in air is about ....... times greater than the speed of sound in air.
- Million
- Trillion
- Billion
- None
An aeroplane travelling at the speed of sound will have a velocity of:
- 1000 km/hr
- 1180 km/hr
- 1540 k/hr
- 1620 k/hr
The correct statement is:
- Sound and light both require medium for propagation.
- Sound can travel in vacuum, but light can not.
- Sound needs medium, but light does not need medium for its propagation.
- Sound and light both can travel in vacuum.