Suppose that the electric field part of an electromagnetic wave in vacuum is E=(3.1N/C)cos[(1.8rad/m)y+(5.4×106rad/s)t]^i(a) What is the direction of propagation?
(b) What is the wavelength λ ?
(c) What is the frequency v?
(d) What is the amplitude of the magnetic field part of the wave?
(e) Write an expression for the magnetic field part of the wave.
(a)Electric field is directed along negative x-direction.
hence the direction of motion is along the negative y-direction.
(b)
From
the given equation, k=1.8 rad/m
λ=2π/k=3.49
(c)
Frequency
of wave is ν=ω/2π=8.6×107=86 Mhz
(d)
For
the given equation, Eo=3.1N/C
Bo=Eo/c=1.03×10−7=103nT
(e)
Magnetic
wave is directed along negative z-direction.
Thus,
B=Bocos(ky+ωt)^k
⇒B=1.03×10−7cos(1.8y+5.4×106t)^k