Physics

Problem

A plane electromagnetic wave in vacuum is described by

E(x,t)=100\,\sin\bigl(20\pi x-6\times10^{9}\pi t\bigr)\;\text{V\,m}^{-1},

where

x

is in metres and

t

in seconds. Find the instantaneous electric field at

x = 0.025\,\text{m}

and

t = 5.0\times10^{-10}\,\text{s}

. a)

+100\,\text{V\,m}^{-1}

-100\,\text{V\,m}^{-1}

0\,\text{V\,m}^{-1}

-60\,\text{V\,m}^{-1}