question_answer

The region between two concentric spheres of radii 'a' and 'b' respectively (see figure), has volume charge density\[\rho =\frac{A}{r}\], where A is a constant and r is the distance from the r centre. At the centre of the spheres is a point charge Q. The value of A such that the electric field in the region between the spheres will be constant, is

A) \[\frac{Q}{2\pi ({{b}^{2}}-{{a}^{2}})}\]

B) \[\frac{2Q}{\pi ({{a}^{2}}-{{b}^{2}})}\]

C) \[\frac{2Q}{\pi {{a}^{2}}}\]

D) \[\frac{Q}{2\pi {{a}^{2}}}\]

Correct Answer: D

Solution :