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NEET UG PHYSICS MCQ: ELECTROMAGNETIC WAVES

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Analyzing +4 | -1

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A : EM waves used for optical communication have longer wavelengths than that of microwave, employed in Radar technology.
Reason R : Infrared EM waves are more energetic than microwaves, (used in Radar)
In the light of given statements, choose the correct answer from the options given below.

View answer and explanation

Correct option: B

A is false but R is true

Option B (A is false but R is true) is correct because EM waves used for optical communication (infrared and visible light) have shorter wavelengths than microwaves, and infrared waves are indeed more energetic than microwaves.

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:-