Question

(a) A hollow cylinder has a charge q coulomb within it as shown in figure. If φ is the electric flux in unit of V-m associated with the curved surface B, what is the flux linked with the plane surface A in the same units?

(b). Four equal charges q each are placed at four corners of a square of side ‘a’ each. What is the work done in carrying a charge –q from its centre to infinity?

(c).(i) The capacity of a body A is 100 times the capacity of body B and charge on A is 10 times the charge on B. When A and B are put in contact with each other, will charge flow from A to B or from B to A? Why?

(ii). Calculate the potential in air at a point 1m away from a charge of 1µc.

Answer 1

(a) According to Gauss’s theorem :

(b) Potential at the centre O of the square due to four equal charges ‘q’ at four corners is :

(c). (i) We know,

∴ Charge will flow from B to A, as potential of B is greater than potential of A.

(ii) We have,