Question

A key of a mechanical piano is struck gently and then struck again, but much harder this time. In the second case:

• A. sound will be louder, but pitch will not be different.
• B. sound will be louder and pitch will also be higher.
• C. sound will be louder, but pitch will be lower.
• D. both loudness and pitch will remain unaffected.

Answer 1

The correct option is A sound will be louder, but pitch will not be different.

The pitch of any sound wave depends on the frequency of the wave and frequency depends on the source. When the mechanical piano is struck harder the second time, we find the sound will be louder, but pitch remains the same because the frequency has not changed. The pitch depends on the frequency of vibration of the particular key which is being hit and hence there will not be a change in the pitch of sound. Loudness depends on amplitude which will be more if the key is struck harder.
Hence, option (a) correct.