Question

Assertion: The flash of lightning is seen before the sound of thunder is heard.
Reason: The sound of thunder is produced after the flash of lightning.
(A) Both the Assertion and Reason are correct and Reason is the correct explanation for Assertion.
(B) Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
(C) Assertion is correct but Reason is incorrect.
(D) Assertion is incorrect but Reason is correct.

Answer 1

Hint
Light is an electromagnetic wave and hence it has a speed which is much higher than the speed of sound. So during lightning, the light reaches earlier than the sound. So the reason is incorrect.

Complete step by step answer
Lightning is a naturally occurring electrostatic discharge which instantaneously releases a huge amount of energy because two electrically charged regions temporarily equalize themselves. Lightning does occur commonly during the thunderstorms and various other types of weather systems.
The flash of lightning during a thunderstorm is a light ray which is an electromagnetic wave. The speed of light in a vacuum is given by $3 \times {10^8}m/s$ which is much more than the speed of the sound.
So when lightning strikes then the flash of light reaches us much faster than the sound does.
But this is not because the sound is produced after the flash of the lightning but rather because of the low speed of sound than the speed of light.
Hence in the given question, the assertion is correct but the reason is incorrect.
So the correct option will be C. Assertion is correct but Reason is incorrect.

Note
The lightning releases a huge amount of energy. This energy is in the form of heat which is much greater than even the surface of the sun. This causes the air to rapidly expand and vibrate which creates the sound of the thunder. There are primarily three types of lightning which are defined by the starting and the ending point of the charges, which are the intra-cloud, cloud-to-cloud, and the cloud-to-ground.