Question

Choose the correct option in each of the following:

The rapid back and forth movement of a body about its mean position is called

• A. Time period
• B. Frequency
• C. Amplitude
• D. Vibration

Answer 1

The correct option is D

Vibration

Explanation of the correct option:

Option D:

Vibration:

1. Sound is a form of energy that is produced when a body vibrates.
2. The particles of the medium do not leave their position but vibrate about their mean position.
3. For example, when a loudspeaker is switched on, a membrane in the loudspeaker vibrates and moves backward and forward. This causes the surrounding air particles to vibrate.

Explanation of the incorrect option:

Option A:

Time Period:

1. Time Period is defined as the time is taken for one complete vibration to pass through a given point. It is denoted by T.
2. The SI unit of the period is second (s).

Option B:

Frequency:

1. It is defined as the number of vibrations in 1 second.
2. Hertz (Hz) is the SI unit of frequency
3. For example, two complete waves pass through a point in 1 second. So, the frequency of the given wave is 2 Hz.

Option C:

Amplitude:

1. It is the maximum displacement of its particles from the mean position. It is denoted by " A ". The SI unit of the amplitude is meter (m).
2. Two waves with the same frequency can have different amplitudes.

So, the correct answer is option (D).