Speed of Sound

Q.

Sound travels fastest in ______.

1. Solid object

2. Gas

3. Water

4. Vacuum

Q. For $1{}^{\circ }\text{C}$ rise in temperature, the velocity of sound in air falls by about $0.6{\text{m s}}^{-1}$.

1. True
2. Cannot say
3. False
4. Depends on the pressure

Q.

Sound waves with a frequency of $20Hz$ to $20,000Hz$ are called_______.

1. Inaudible sounds

2. Infrasonics

3. Ultrasonics

4. Audible sounds

Q.

A sound wave has a frequency of $1000Hz$ and a wavelength of $34cm$. How long will it take to travel $1km$?

1. 3.20s

2. 2.94s

3. 5.94s

4. 3.10s

Q. The time taken to complete one oscillation is called ___________.

1. time period
2. frequency
3. amplitude
4. intensity

Q. Which of the following factors affect the velocity of sound in a medium?

1. Density
2. Temperature
3. Humidity
4. All of the above.

Q.

In which medium does sound travel slowest?

1. Liquids

2. Vacuum

3. Solids

4. Gases

Q.

A string fixed at both ends oscillates in $5$ segments, length $10m$ and the velocity of the wave is $20m{s}^{-1}$. What is the frequency?

1. $5Hz$

2. $15Hz$

3. $10Hz$

4. $2Hz$

Q. The relation between the velocity (v) of sound in a medium and the density (ρ) of the medium is given by.

1. $\text{v}\propto {\rho }^{-\frac{1}{2}}$
2. $\text{v}\propto \rho$
3. $\text{v}\propto {\rho }^{-1}$

Q.

What is despersive medium is all medium are despersive medium give some examples of dispersive medium

Q.

Sound waves cannot travel through

1. Solids

2. Liquids

3. Gases

4. Vacuum

Q. At what temperature (in ${}^{\circ }\text{C}$) will the velocity of sound in air be $1.5$ times its velocity at $0{}^{\circ }\text{C}$? (The velocity of sound in air at $0{}^{\circ }\text{C}=330{\text{m s}}^{-1}$)

1. $409.50{}^{\circ }\text{C}$
2. $614.25{}^{\circ }\text{C}$
3. $136.50{}^{\circ }\text{C}$
4. $341.25{}^{\circ }\text{C}$

Q.

A wave passes from one medium to another medium. Mention one property of the wave, out of speed, frequency or wavelength

(a) which changes,

(b) which does not change.

Q. When sound waves travel from a rarer medium to a denser medium, its speed:

1. decreases

2. may increase or decrease

3. remain constant

4. increases

Q.

The speed of sound in water is nearly
1500 m/s.

1. True
2. False

Q.

A construction worker’s helmet slips and falls down when he is $78.4m$ above the ground. He hears the sound of the helmet hitting the ground $4.23$ seconds after it has slipped. Find the speed of sound in air. ( Acceleration due to gravity $9.8m/s^2$ )

1. 512 m/s

2. 341 m/s

3. 651 m/s

4. 215 m/s

Q. If the frequency of a sound wave is doubled, what will be the ratio of the new speed to the old speed of sound?

1. 1
2. 2
3. 3
4. 4

Q. The velocity of sound in a solid medium varies with the elastic modulus ($\text{E}$) of the medium as:

1. ${\text{E}}^{-0.5}$
2. ${\text{E}}^2$
3. ${\text{E}}^{0.5}$
4. ${\text{E}}^{-1}$

Q. Among air, water, and iron, sound travel faster in ____.

1. air
2. water
3. iron
4. both air and water

Q. A person standing at a distance $x$ in front of a cliff fires a gun. Another person B standing behind the person A at a distance $y$ from the cliff hears two sounds of the fired shots after $2s$ and $3s$ respectively. Calculate $x$ and $y$ (take speed of sound 320 $m{s}^{-1}$)​

Q.

Two points on a traveling wave having frequency $500Hz$ and velocity $300\frac{m}{s}$ are $60°$ out of phase, then the minimum distance between the two points is

1. $0.2$

2. $0.1$

3. $0.4$

4. $0.5$

Q. At what temperature (in ${}^{\circ }\text{C}$) will the velocity of sound in air be triple its velocity at $0{}^{\circ }\text{C}$? (The velocity of sound in air at $0{}^{\circ }\text{C}=330{\text{m s}}^{-1}$)

1. 2184

Q.

The longitudinal waves travel in a coiled spring at a rate of $4m/s$. The distance between two consecutive compressions is $20cm$. Find the frequency of the wave?

1. 15 hertz

2. 20 hertz

3. 25 hertz

4. 30 hertz

Q. If a wave completes 500 oscillations in 10 seconds. Find the frequency of the wave.

1. 5 Hz
2. 50 Hz
3. 500 Hz
4. 0.5 Hz

Q. When a source moves away from a stationary observer, the frequency is 6/7 times the original frequency. Given: speed of sound = 330 m/s. The speed of the source is

1. 40 m/s
2. 55 m/s
3. 330 m/s
4. 165 m/s
   

Q. Statement A: The product of time period and the frequency of a sound wave is always 1.
Statement B: Time period is expressed in the units of seconds.
Which of the statement is correct?

1. Statement A only
2. Statement B only
3. Both statments A and B
4. Neither statement A nor B

Q. Find the frequency of a wave with a time period of $0.001seconds$.

1. $1000Hz$
2. $100Hz$
3. $10Hz$
4. $0.01Hz$

Q.

Sound travels at the fastest speed in which medium?

1. Air

2. Solids

3. Liquids

4. Equal in all mediums

Q.

Do all EM waves travel at same speed?

Q.

A sound produced on the surface of a lake takes 4.5 s to reach a boatman. How much time will it take to reach a driver inside water at the same distance if speed of sound in water is 4.5 times the speed of sound in air?

1. 1 s
   

2. 2 s
   

3. 3 s
   

4. 4 s