Question

Assertion:A charged cloud induces an opposite charge on a conductor
Reason:The surface charge density at the sharp pointed end is very high, some charge leaks away setting an oppositely charged electric wind.
A) Both assertion and reason are correct and reason is the correct explanation for the assertion.
B) Both assertion and reason are correct but reason is not the correct explanation for the assertion
C) Assertion is correct but reason is incorrect
D) Both assertion and reason are incorrect

Answer 1

This phenomenon can be understood by the logic of lightning strikes. Lightning from a cloud strikes upon some bodies as there is some potential difference developed between the cloud and the body which is possible if they both develop some amount of opposite charges to each other.

Complete answer:
A charged cloud does induce an opposite charge on conductors. This is similar to the induction of charge in a metal sphere connected to the ground, when another charged sphere is brought near it. The charge induced is opposite to the charge of the metal sphere that is brought near the sphere in which charge is induced.
Hence, the assertion is correct.
The surface charge density is indeed high at the sharp pointed ends, since a lot of charge is accumulated in a small region. Such high amounts of charge density causes some of the charge to leak away into the surrounding air and it is carried away by wind. Thus, the wind essentially carries a charge opposite to the cloud and hence, is an oppositely charged wind with respect to the cloud. This wind can also transfer this charge to the cloud and decrease the potential difference developed between the conductor and the cloud. This can decrease the chances of a lightning strike.
Hence, the reason is also correct. However, the reason is not the correct explanation for the assertion.

Therefore, the correct option is B) Both assertion and reason are correct but reason is not the correct explanation for the assertion.

Note:
The above explanation is also the reason why sharp pointed conductors are placed on top of buildings. These pointed conductors are connected to the ground and all the charge that gets accumulated in the tips gets transferred to the ground thus neutralizing the potential difference that would have formed between the cloud and the building. This saves the building from lightning strikes.