The magnetic component of a plane electromagnetic wave travelling in free space along…

PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Waves Sound and Physical Optics · Waves Sound and Physical Optics

Problem

The magnetic component of a plane electromagnetic wave travelling in free space along the

+x

-direction is represented by

B(x,t)=2.0\times10^{-7}\cos\bigl(5\pi\times10^{6}t-0.016\pi x\bigr)\;\text{T},

where

x

is in metres and

t

in seconds. Answer the following: (i) Calculate the amplitude of the corresponding electric field. (ii) Write down the expression for the electric field

E(x,t)

, stating its direction. (iii) Determine the instantaneous values of

E

and

B

at the point

x=5.0\,\text{m}

and time

t=2.0\,\mu\text{s}

. (iv) Compute the phase of the wave at this space–time point and state whether the fields are near a crest, a trough, or an intermediate position on the wave.

Related theory

Wave Description
Nature of EM Waves
Electromagnetic Waves
Displacement current and waves
Electromagnetic waves and their nature

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