EASY

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Which of the following explain that all galaxies are receding from us?

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Important Questions on Wave Optics

EASY

Physics>Optics>Wave Optics>Doppler Effect in Light

The shape of wave front at a very large distance from source is ________.

MEDIUM

Physics>Optics>Wave Optics>Doppler Effect in Light

The wavelength of light coming from a star shifts towards the violet end of the spectrum. This shows that star is

MEDIUM

Physics>Optics>Wave Optics>Doppler Effect in Light

A galaxy is moving away from the earth at a speed of $286 km s^{- 1}$ . The shift in the wavelength of a red line at $630 nm$ is $x \times 10^{- 10} m$ . The value of $x$ , to the nearest integer, is ___ .

[Take the value of the speed of the light $c$ , as $3 \times 10^{8} m s^{- 1}$ ]

EASY

Physics>Optics>Wave Optics>Doppler Effect in Light

Huygens' wave theory of light cannot explain.

MEDIUM

Physics>Optics>Wave Optics>Doppler Effect in Light

With what speed should a galaxy move outward with respect to earth so that the sodium-

D

line at wavelength

5890 \overset{\circ}{A}

is observed at

5896 \overset{\circ}{A} ?

EASY

Physics>Optics>Wave Optics>Doppler Effect in Light

The wave front is a surface in which

MEDIUM

Physics>Optics>Wave Optics>Doppler Effect in Light

For a specific wavelength

670 nm

of light coming from a galaxy moving with velocity

v

, the observed wavelength is

670.7 nm

. The value of

v

MEDIUM

Physics>Optics>Wave Optics>Doppler Effect in Light

A submarine

A

travelling at

18 km {hr}^{- 1}

is being chased along the line of its velocity by another submarine

B

travelling at

27 km {hr}^{- 1}

B

sends a sonar signal of

500 H z

to detect

A

and receives a reflected sound of frequency

v

. The value of

v

is closed to (Speed of sound in water

1500 m s^{- 1}

)

MEDIUM

Physics>Optics>Wave Optics>Doppler Effect in Light

A star emitting light of wavelength

5896 \overset{o}{A}

is moving away from the earth with a speed of

3600 km / s

. The wavelength of the light observed on the earth will

EASY

Physics>Optics>Wave Optics>Doppler Effect in Light

If a star emitting orange light moves away from the earth, its colour

EASY

Physics>Optics>Wave Optics>Doppler Effect in Light

When light propagates through a material medium of relative permittivity

ϵ_{r}

and relative permeability

μ_{r}

, the velocity of light,

v

is given by : (

c

- velocity of light in vacuum)

MEDIUM

Physics>Optics>Wave Optics>Doppler Effect in Light

A sound source S is moving along a straight track with speed

v

, and is emitting sound of frequency

v_{0}

.An observer is standing at a finite distance, at the point

O,

from the track. The time variation of frequency heard by observer is best represented by : (to represents the instant when the distance between the source and observer is minimum)

EASY

Physics>Optics>Wave Optics>Doppler Effect in Light

An observer is moving with half the speed of light towards a stationary microwave source emitting waves at frequency

10 GHz

. What is the frequency of the microwave measured by the observer? (speed of light

= 3 \times 10^{8} m s^{- 1}

)

EASY

Physics>Optics>Wave Optics>Doppler Effect in Light

Considering the fact that the speed of light in glass is not independent of the colour of light, which of the statement is true?

EASY

Physics>Optics>Wave Optics>Doppler Effect in Light

Two cars A and B are moving away from each other in opposite directions. Both the cars are moving with speed of

20 m s^{- 1}

with respect to the ground. If an observer in car A detects a frequency

2000 H z

of the sound coming from car B, what is the natural frequency of the sound source in car B?
(speed of sound in air

= 340 m s^{- 1}

)

HARD

Physics>Optics>Wave Optics>Doppler Effect in Light

A police man on duty detects a drop of

15 %

in the pitch of the horn of a motor car as it crosses him. If the velocity of sound is

330 m s^{- 1},

calculate the speed of the car

EASY

Physics>Optics>Wave Optics>Doppler Effect in Light

A source of sound

S

is moving with a velocity of

50 m s^{- 1}

towards a stationary observer. The observer measures the frequency of the source as

1000 H z .

What will be the apparent frequency of the source when it is moving away from the observer after crossing him? (Take velocity of sound in air is

350 m s^{- 1}

)

MEDIUM

Physics>Optics>Wave Optics>Doppler Effect in Light

If a star emitting orange light moves away from the Earth, its colour will

EASY

Physics>Optics>Wave Optics>Doppler Effect in Light

A galaxy moves with respect to the earth so that Sodium line of

589.0 nm

is observed at

589.6 nm .

The speed of the galaxy is

EASY

Physics>Optics>Wave Optics>Doppler Effect in Light

Due to Doppler's effect the shift in wavelength observed is

0.1 Å

for a star producing wavelength

6000 Å

. Velocity of recession of the star will be

Which of the following explain that all galaxies are receding from us?

Important Questions on Wave Optics

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