Question

A plane electromagnetic wave is incident on a material surface. If the wave delivers momentum $$p$$ and energy $$E,$$ then

A. $$p = 0,E = 0$$
B. $$p \ne 0,E \ne 0$$  
C. $$p \ne 0,E = 0$$
D. $$p = 0,E \ne 0$$
Answer :   $$p \ne 0,E \ne 0$$
Solution :
$$EM$$  waves carry momentum and hence can exert pressure on surfaces. They also transfer energy to the surface so $$p \ne 0$$  and $$E \ne 0.$$

Releted MCQ Question on
Electrostatics and Magnetism >> Electromagnetic Waves

Releted Question 1

Out of the following options which one can be used to produce a propagating electromagnetic wave?

A. A stationary charge
B. A chargeless particle
C. An accelerating charge
D. A charge moving at constant velocity
Releted Question 2

The energy of the $$EM$$  waves is of the order of $$15\,keV.$$  To which part of the spectrum does it belong?

A. X-rays
B. Infrared rays
C. Ultraviolet rays
D. $$\gamma $$-rays
Releted Question 3

The condition under which a microwave oven heats up a food item containing water molecules most efficiently is

A. the frequency of the microwave must match the resonant frequency of the water molecules
B. the frequency of the microwave has no relation with natural frequency of water molecules
C. microwave are heat waves, so always produce heating
D. infra-red waves produce heating in a microwave oven
Releted Question 4

The electric field associated with an electromagnetic wave in vacuum is given by $$E = \hat i40\cos \left( {kz - 6 \times {{10}^8}t} \right),$$      where $$E,z$$  and $$t$$ are in $$volt/m,$$  metre and second respectively. The value of wave vector $$k$$ is

A. $$2\,{m^{ - 1}}$$
B. $$0.5\,{m^{ - 1}}$$
C. $$6\,{m^{ - 1}}$$
D. $$3\,{m^{ - 1}}$$

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Electromagnetic Waves


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