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NEET UG PHYSICS MCQ: ELECTROMAGNETIC WAVES

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Analyzing +4 | -1

When an electromagnetic waves enter the ionised layer of ionosphere, the motion of electron cloud produces a space current and the electric field has its own capacitative displacement current, then

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Correct option: B

the space current lags behind the displacement current by a phase

180^{\circ}

.

Option B is correct because the space current, caused by the motion of electrons, lags behind the displacement current by 180 degrees due to the inertia of the electrons.

More Questions from ELECTROMAGNETIC WAVES

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What is order of energy of X-rays (

{E_X}

), radio waves (

{E_R}

) and microwave (

{E_M}

)? The amplitude of the sinusoidally oscillating electric field of plane wave is

60\,\,\frac{V}{m}

. Then the amplitude of the magnetic field is An EM wave from air enters a medium. The electric fields are

{E_1} = {E_{01}}\hat x\cos \left[ {2\pi v\left( {\frac{z}{c} - t} \right)} \right]

{E_2} = {E_{02}}\hat x\cos \left[ {k\left( {2z - ct} \right)} \right]

in medium, where the wave number k and frequency ν refer to their values in air. The medium is non-magnetic.
If

{\varepsilon _{{r_1}}}

{\varepsilon _{{r_2}}}

refer to relative permittivities of air and medium respectively, which of the following options is correct? Electric field in a plane electromagnetic wave is given by

E = 50\sin \,(500x - 10 \times {10^{10}}t)\,v/m.

The velocity of electromagnetic wave in this medium is
(Given,

c

= speed of light in vacuum) If an electromagnetic wave is propagation in a medium with permeability 

\mathrm{\varepsilon }

and permittivity

\mathrm{\mu }

\sqrt {\frac{\mathrm{\mu }}{\mathrm{\varepsilon }}}

is the In an E.M. wave the average energy density is associated with:-