Question

(A) Light is a form of electromagnetic radiation and a non-mechanical wave.
(B) Light waves do not require a material as a medium for propagation.
A. Only A is true
B. Only B is true
C. Both A and B are true
D. Both A and B are false

Answer 1

Hint: The electromagnetic radiation is the radiation which has both electric and magnetic field components propagating perpendicular to each other. The electromagnetic wave can transfer the energy in the vacuum but the mechanical wave cannot transfer the energy in the vacuum. Only the mechanical waves require a material medium for their propagation.

Complete answer:
We will check both the statements to answer this question. To do so, let’s discuss the meaning of electromagnetic radiation and mechanical waves.As we know, the electromagnetic radiation is the radiation which has both electric and magnetic field components propagating perpendicular to each other. We know that the light wave is a propagating wave of electric and magnetic fields. Therefore, we can say that the light wave is the form of electromagnetic radiation.

We differentiate the electromagnetic wave and mechanical wave by their ability of transfer of energy through a vacuum. The electromagnetic wave can transfer the energy in the vacuum but the mechanical wave cannot transfer the energy in the vacuum. Therefore, we can say that the light wave is a non-mechanical wave.So, the statement A is true.

Now, let’s discuss the second statement. We know that only mechanical waves require a medium for their propagation. Since the light wave is the non-mechanical wave, it can propagate even in the vacuum. Therefore, the light wave does not require the medium for its propagation.Thus, the statement B is also true.

So, the correct answer is option C.

Note: Unlike light wave, sound wave is a mechanical wave and thus it requires a medium for its propagation. Students must know that the electromagnetic wave is a transverse wave and mechanical wave is generally a longitudinal wave. In the transverse wave, the particles of the medium vibrate up and down, while in the longitudinal wave, the particles vibrate back and forth is the direction of propagation.