Assertion: The lightening conductor at the top of high building has sharp pointed ends.
Reason: The surface density of charge at sharp points is very high resulting in setting up of electric wind.

Options

A. If both assertion and reason are true and reason correct explanation of assertion.
B. If both assertion and reason are true but reason the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Answer

A

Explanation

We know that surface density of charge is very large on the sharp ends of a conductor. This charge from pointed ends sets up a charged electric wind. This charged electric wind comes in contact with the charged cloubs and then source of its building neturalised and so potential drops between building is reduced. Even if lightning strikes the building, charge is conducted by the lightning conductor to the earth and there is no harm to building.