The magnetic field in a plane electromagnetic wave is given by `B_(y) = 2xx10^7 T sin (0.5xx10^3x+1.5xx10^11 t) T`
(a) What is the wavelength and frequency of the wave?
(b) Write an expression for the eletric field.

Options

A. a visible light
B. an infrared wave
C. a microwave
D. a radio wave

Answer

C

Explanation

We have, `B_(y) = 2 xx 10^(-7) sin(0.5 xx 10^(3)x + 1.5 xx 10^(11)t)`
Comparing with the standard equation, we get
`B_(y) = B_(0) sin (kx + omegat)`
`k = (0.5 xx 10^(3))`
`lambda = (2pi)/(0.5 xx 10^(3)) = 0.01256 (":' lambda = (2pi)/(k))`
The wavelength range of microwaves is `10^(-3)` to `0.3`. The wavelenght of this wave lies between `10^(-3)` to `0.3`, so the equation represents a microwave.