The frequency of a man's voice is `200 Hz` and its wavelength is `2 m`. If the wavelength of a child's voice in `1 m`, then the frequency of the child's voice is :

Options

A. 200 Hz
B. 25 Hz
C. 100 Hz
D. 400 Hz

Answer

D

Explanation

Since the wavelength of child's voice (1 m) is half that ma's voice (2 m), the frequency of child's voice is double that of man's voice (i.e., 400 Hz) as `v = v//lamda` or `prop 1//lamda`(v being constant).