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Let P (r) = Q π R 4 r be the charge density distribution for a solid sphere of radius R and total charge Q . For a point p inside the sphere at distance r 1 from the centre of the sphere, the magnitude of the electric field is

Options

  1. AZero
  2. BQ 4 π   ε 0   r 1 2
  3. CQ r 1 2 4 π ε 0 R 4
  4. DQ   r 1 2 3 π   ε 0   R 4

Correct answer

C. Q r 1 2 4 π ε 0 R 4

Step-by-step solution

P ( r ) = Q π R 4 r From Gauss law ∮ E . d s = q e n ε 0 = ∫ ρ V d V ε 0 = ∫ O r 1 Q r 4 π r 2 d r π R 4 / ε 0 E .4πr 1 2 = Q π R 4 4 π r 1 4 4 ε 0 E= Qr 1 2 4πε 0 R 4

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