Microwaves from a transmitter are directed normally toward a plane reflector. A detector moves along the normal to the reflector. Between positionsof 14 m successive maxima the detector travels a distance 0.14 m. The frequency of the transmitter is `(c = 3 xx 10^(8) m s^(-1))`.

Options

A. `1.5 xx 10^(10) Hz`
B. `10^(10) Hz`
C. `3 xx 10^(10) Hz`
D. `6 xx 10^(10) Hz`

Answer

a

Explanation

The detector receives direct as well as reflected waves. The distance moved between two consecutive position of maxima is `lambda//2`.
`14 xx (lambda)/(2) = 71 = 0.14 m`
`implies lambda = 0.02 m`
`c = n lambda`
Putting `c = 3 xx 10^(8) m//s`, we have
`n = (c)/(lambda) = (3 xx 10^(8))/(0.02) = 1.5 xx 10^(10) Hz`.