Question

When you speak to your friend, which of the following parameters has a unique value in the sound produced?

• A. frequency
• B. velocity
• C. amplitude
• D. wave length

Answer 1

The correct option is B

velocity

An explanation for the correct option.

Out of the given options,

1. Wave velocity has a unique value. Because both the friends are producing the sound in the same medium, wave velocity depends upon a medium, which is not changing here.
2. The amplitude of the sounds depends upon the energy given by any of the friends to sound, so it may change.
3. The frequency of sound depends upon the thickness of the vocal cords of two friends, so it also may vary.
4. Now, the wavelength is inversely proportional to the frequency. $\lambda \alpha \frac{1}{f}$
   For a constant velocity, when frequency $f$ changes, the wavelength'$\lambda$' will also change.

Hence option ‘b’ is the correct answer.