Resonance in Sound Waves

Q.

State the condition for the resonance to occur.

Q.

What is the formula to calculate the pitch of a screw gauge?

Q.

How does an $LC$ oscillator work?

Q.

When a troop crosses a suspension bridge, the soldiers are asked to break their steps. Why?

Q.

In Fig. 7.15, A, B, C and D are the four pendulums suspended from the same elastic string XY. The lengths of pendulum A and D are equal, while the length of pendulum B is shorter and of the pendulum C is longer. The pendulum A is set into vibrations.

(a) What is your observation about the virbations of pendulum D ? (b) Give reason for your observation in part (a). (c) What type of vibrations take place in pendulums B and C ? (d) Give reason for the answer in part (c) .

Q.

A tuning fork of frequency 256 Hz will resonate with another tuning fork of frequency:

1. 128 Hz
   

2. 256 Hz
   

3. 384 Hz
   
   

4. 500 Hz

Q. What are sympathetic vibrations ? What are its examples ?

Q.

An earthquake produces which type of sound wave before the main shock wave begins?

1. Infrasonic

2. Audible sound

3. Supersonic

4. Ultrasonic

Q.

What happens when frequencies matches the natural frequency?

Q.

How do you tune your radio set to a particular station ? Name the phenomenon involved in doing so and define it.

Q.

What is the difference between scalar and vector quantities?

Q.

What is meant by resonance? Describe a simple experiment to illustrate the phenomenon of resonance and explain it.

Q.

Why is a loud sound heard at resonance ?

Q.

A musician using an open flute of length $50cm$ produces second harmonic sound waves. A person runs towards the musician from another end of a hall at a speed of $10km/h$. If the wave speed is $330m/s$, the frequency heard by the running person shall be close to

1. $666Hz$

2. $753Hz$

3. $500Hz$

4. $333Hz$

Q.

In Fig. 7.15, A, B, C and D represent the test tubes each of height 20 cm which are filled with water up to heights of 12 cm, 14 cm, 16 cm and 18 cm respectively. If a vibrating tuning fork is placed over the mouth of test tube D, a loud sound is heard.

(a) Describe the observations with the tubes A, B and C when the vibrating tuning fork is placed over the mounth of these tubes.

(b) Give the reason for your observation in each tube.

(c) State the principle illustrated by the above experiment.

Q.

How are phonons created?

Q.

The figure shows two tuning forks A and B of the same frequency mounted on two separate sound boxes with their open ends facing each other. The fork A is set into vibration.

(a) Describe your observation.

(b) State the principle illustrated by this experiment.

Q.

Write the steps to measure the diameter of a thin wire using screw gauge.

Q.

Two objects are in resonance, then:

1. both of them have the same frequency.

2. both of them have a different frequency.

3. the vibration of both bodies are in phase.

4. the vibration of both bodies are out of phase.

Q.

It is observed during an earthquake in japan that medium sized buildings are damaged more than very short or tall buildings. This is because

1. The natural frequency of the medium sized buildings may be very different from the frequency of the earth quake

2. The forced frequency of the medium sized buildings may be similar to the frequency of the earth

3. The natural frequency of the medium sized buildings may be similar to the frequency of the earth quake

4. The resonance frequency of the medium sized buildings may be similar to the frequency of the earth

5. The natural frequency of the medium sized buildings may be similar to the frequency of the earth

Q.

What is the pendulum wave?

Q.

A vibrating tuning fork, held over an air column of a given length with its one end closed, produces a loud audible sound. Name the phenomenon responsible for it and explain the observation.

Q.

A tuning fork of frequency 256 Hz will resonate with another tuning fork of frequency :

(a) 128 Hz (b) 256 Hz

(c) 384 Hz (d) 512 Hz.

Q.

Complete the following sentence :

Resonance is a special case of ........ vibrations, when frequency of the driving force is ........... natural frequency of the drivens body.

Q.

Why are the stringed instruments like guitar provided with a hollow sound box ?

Q.

Stems of 2 vibrating tuning forks A and B are touched to the wooden box of a sinister.It is observed that the paper rider (a small piece of paper folded at the centre.)present on the wire flies off when the stem of vibrating tuning fork B is touched to the wooden box but the paper just vibrates when the stem of vibrating tuning fork A is touched to the wooden box.

I) Name the phenomenon when the paper rider just vibrates.

2)Name the phenomenon when the paper rider flies off.

3)Why the paper rider fly off when the stem of tuning fork B is touched to the box?

Q.

A certain sound has a frequency of 256 Hz and wavelength of 1. 3 m. calculate the speed with which this sound Travels .what difference would be felt by a listner between this sound and another sound travelling at the same speed but of wavelength 2. 6 m?

Q.

What is Harmonic in Electrical?

Q.

The sound is produced because of _______ of a particle.

1. Vibrations

2. Charge

3. None of these

4. Rotations

Q.

Sound is produced by a ________ body.