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QJEEAdv08Phdfa8: JEE Advanced 2008 Physics - Class 12 JEEAdv08Phdfa8 Solution: STATEMENT 1 : For practical purposes, the earth is used as a…

STATEMENT 1 : For practical purposes, the earth is used as a reference at zero potential in electrical circuits.

and

STATEMENT 2 : The electrical potential of a sphere of radius R with charge Q uniformly distributed on the surface is given by Q4πε0R{Q \over {4\pi {\varepsilon _0}R}}

Multiple Choice Options

  • A Statement 1 is True, Statement 2 is True; Statement 2 is a CORRECT explanation for Statement 1
  • B Statement 1 is True, Statement 2 is True; Statement 2 is a NOT CORRECT explanation for Statement 1
  • C Statement 1 is True, Statement 2 is False
  • D Statement 1 is False, Statement 2 is True

Step-by-Step Verified Solution

Statement 1 is True.

The earth is used as a reference with zero potential. The reasons are :

(i) Due to large size of the earth, its potential does not change even if a small amount of charge is given to the earth or taken away from it. Also, all conductors on the earth which are not given any external charge, are very nearly at the potential Ve. The choice of reference is quite arbitrary and is largely governed by convenience.

(ii) The earth is a good conductor. It is easily accessible for electrical circuits geographically distributed over it and hence it is used as a common reference with zero potentil.

Statement 2 is true.

IIT-JEE 2008 Paper 2 Offline Physics - Electrostatics Question 8 English Explanation

V = Q4πε0R{Q \over {4\pi {\varepsilon _0}R}}

Therefore, statement 2 is correct explanation for statement 1.

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