(a) Identiy the part of the electromagnatic spectrum used in (i) radar and (ii) eye surgery. Write their frequency range.
(b) Prove that the average energy density of the oscillating electric field is equal to that of the oscilating magnetic field.

Explanation

(b) Average energy density of oscillating electric field :
`mu_(E)=1/2in_(0)E_("rms")^(2)" ....(1)"`
Average energy density of oscillating magnetic field :
`mu_(B)=1/(2mu_(0))B_(rms)^(2)" ....(2)"`

`B_(rms)=E_(rms)/CandC=1/sqrt(mu_(0)in_(0))`
`B_(rms)=E/(1/sqrt(mu_(0)in_(0)))=E_(rms)sqrt(mu_(0)in_(0))`
Substituting the above value in equation (2)
`mu_(B)=1/(2mu_(0))E_(rms)^(2)mu_(0)in_(0)`
`mu_(B)=1/2in_(0)E_(rms)^(2)=mu_(E)`