Q 1 :    

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: The potential (V) at any axial point, at 2 m distance (r) from the centre of the dipole of dipole moment vector P of magnitude, 4×10-6C m, is ±9×103 V.

Reason R: V=±2P4π0r2, where r is the distance of any axial point, situated at 2 m from the centre of the dipole.

In the light of the above statements, choose the correct answer from the options given below.                [2024]

  • Both A and R are true and R is the correct explanation of A.

     

  • Both A and R are true and R is NOT the correct explanation of A.

     

  • A is true but R is false.

     

  • A is false but R is true.

     

(3)

Potential at any axial point of a dipole is

V=±|p|4πε0r2

   V=±4×10-6×9×109(2)2=±9×103V

So, assertion is true but reason is false.



Q 2 :    

A short electric dipole has a dipole moment of 16×10-9C m. The electric potential due to the dipole at a point at a distance of 0.6 m from the centre of the dipole, situated on a line making an angle of 60° with the dipole axis is (14πε0=9×109 N m2/C2)            [2020]

  • 50 V

     

  • 200 V

     

  • 400 V

     

  • zero

     

(2)

Potential due to dipole, V=p·r^4πε0r2=kpcosθr2

or    V=(9×109)(16×10-9)×cos60°(0.6)2=200V