The electric field of an EM wave in free space is given by $E = 10 \cos (10^7t+kx)\hat j\, V/m$ where t and
x are in sec and meter respectively. It can be inferred that:
(A) The wavelength A is 182.4 m
(B) The wave number k is 0.033 rad/m
(C) The wave amplitude is 10 V/m
(D) The wave is propagating along + Y direction
Which of the following pairs of statement are correct?
Answer & explanation
Correct answer: option 3
The correct answer is Option (4) → (A) and (C)
Give the electric field equation,
$E=10\cos(10^7t+kx)\hat j\,V/m$
and,
Amplitude, $A=10V/m$
and,
$C=\frac{ω}{k}⇒k=\frac{ω}{c}=\frac{10^7}{3}$
$=0.033\,rad/m$
and wave is travelling in +x direction.