Question

When the frequency of a sound wave is increased, which of the following decrease? (1)amplituted (2)period (3)wavelength

Answer 1

Two of them will, for two separate reasons.

Explanation:

Firstly, frequency is defined as being the number of complete waves per second that pass a stationary object/point. Period is defined as the time for one full wave to pass, thus `f (Hz) = 1/(T (s))` So period will fall if frequency rises.

Secondly, the wave equation, `v = f xx lambda` so if v remains constant any increase in frequency must cause a reduction in wavelength. So wavelength decreases as frequency increases.

Finally amplitude (which can be thought of as wave ‘height’ which relates to brightness for light and loudness for sound) is completely independent of frequency (colour for light, or pitch for sound.)