Doppler Effect

Q.

If an observer is moving away from the stationary source of sound, then apparent frequency is given by _________. ($f,V_s,V_0,C$ are frequency, velocity of source, velocity of observer and velocity of sound, respectively).

1. $f\left[\frac{C-V_0}{C}\right]$

2. $f\left[\frac{C+V_0}{C}\right]$

3. $f\left[\frac{C}{C+V_0}\right]$

4. $f\left[\frac{C}{C-V_0}\right]$

Q.

Assertation(A): When a source moves towards a stationary observer, the wavelength of the sound received by the observer decreases.

Reason(R): Doppler effect is applicable only when the velocities of source of the sound and observer are less than the velocity of sound.

1. A and R are true and R is the correct explanation o A.

2. A and R are true, but R is not the correct explanation of A.

3. A is true but R is false.

4. Both A and R are false.

Q. Doppler effect is not seen when the source and the listener are

1. at rest
2. moving with different velocities
3. moving with the same velocity
4. (a) and (c) above.

Q. The relative motion between a source of sound and listener causing an apparent change in the frequency of perceived sound, is called:

1. Oersted's effect
2. Archimedes' effect
3. Doppler effect
4. Placebo effect

Q.

Why PPM is better than PWM?

Q. How come velocity of the sound is inversely proportional to the square root of density? We know that sound speed increase in an increase in density. Explain

Q.

A radar sends a signal to an aeroplane at a distance 45 km away with a speed of 3 x 10⁸ m/s.

The time interval after which the signal will be received back from the Aeroplane is:

1. 3 x 10 ^-4 s

2. 1.5 x 10 ^-4 s

3. 5 x 10 ^-4 s

4. 6 x 10 ^-4 s

Q. Consider a wave represented by $y=aco{s}^2(\omega t-kx)$ where symbols have their usual meanings. This wave has

1. an amplitude a, frequency , and wavelength
2. an amplitude , frequency , and wavelength
   
3. am amplitude , frequency , and wavelength
4. an amplitude a, frequency , and wavelength

Q. Doppler Effect can be used to track artificial satellites.

1. True
2. False

Q.

Does Snells law apply to sound waves

Q.

If the reading on the pitch scale crossed by the head scale is P.S.R, the head scale division that coincides with the pitch scale axis be H.S.C and the zero correction is Z.C, then what is the formula to find the diameter of the wire?

Q.

Does the Doppler effect depend on distance?

Q. Doppler Effect is observed when the source and the observer are stationary.

1. True
2. False

Q. The figure below is a representation of a simple harmonic progressive wave, progressing in the negative X- axis, at a given instant. The direction of the velocity of the particle at state P in the figure is best represented by the arrow.

1. 
2. 
3. 
4. 

Q.

Three musical instruments give out notes at the frequencies listed below:
Flute: 400 Hz; Guitar: 200 Hz; Trumpet: 500 Hz

The one with the highest pitch is

1. Flute

2. Guitar

3. Trumpet

4. All of them have the same pitch

Q. What is red shift?

Q. What is Doppler Effect? Explain with an example.

Q. A stationary source producing a sound of frequency $900\text{Hz}$. What will be the frequency of the sound heard by the listener revolving around the source with a uniform velocity of $8{\text{m s}}^{-1}$? (velocity of sound is $350{\text{m s}}^{-1}$)

1. $920\text{Hz}$
2. $880\text{Hz}$
3. $0\text{Hz}$
4. $900\text{Hz}$

Q.

Which of the above two graphs (a) and (b) (Fig.) representing the human voice is likely to be the male voice? Give the reason for your answer.

Time \( ( m ) \longrightarrow \)

Q. Pick an application where Doppler effect is used:

1. LASER
2. RADAR
3. MRI scan
4. Rear-view mirror

Q.

A wire, fixed at both ends is seen to vibrate at a resonant frequency of $240Hz$ and also at$320Hz$

$\left(a\right)$What could be the maximum value of the fundamental frequency$?$

$\left(b\right)$ If transverse waves can travel on this string at a speed of $40m{s}^{-1}$, what is its length$?$

Q. Explain what is Doppler effect in sound and state its any four applications.

Q. What is radial wave function probability density

Q. A source and an observer move away from each other with a velocity of $10m/s$ with respect to ground. If the observer finds the frequency of sound coming from the source as $1950Hz$, then actual frequency of the source is (Velocity of sound in air $=340m/s$)

1. $1950Hz$
2. $2068Hz$
3. $2132Hz$
4. $2486Hz$

Q.

How is the doppler effect calculated?

Q. In doppler effect

1. only frequency changes
2. both speed and frequency change
3. both intensity and frequency change
4. only speed changes.

Q. A siren placed at a railway platform is emitting sound of frequency $5kHz$. A passenger sitting in a moving train A records a frequency of $5.5kHz$ while the train approaches the siren. During his return journey in a different train $B$ he records a frequency of $6.0kHz$ while approaches the same siren. The ratio of the velocity of train $B$ to that train $A$ is

1. $2$
2. $11/6$
3. $5/6$
4. $242/252$

Q. Explain what is Doppler effect in sound and state its any 'four' applications.

Q. What is full wave rectifier?

Q. The Doppler effect is applicable for

1. Light waves only
2. Sound waves only
3. Both light and sound waves
4. None of the above