InterviewSolution
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InterviewSolution
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A charge `+Q`, is uniformaly distributed within a sphere of radius R. Find the electric field, due to this charge distribution, at a point distant r form the centre of the spehre where : (i) ` 0 lt r lt R` and `(ii) r gt R` |
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Answer» (i) `O lt r lt R`, (ii) Charge per unit volume ` rho= (Q)/((4)/(3)piR^3)` When point P is inside `(o lt r R)` then, charge enclosed by sphere of radius r will be `(4)/(3)pi R^2xx rho`. `=(4)/(3) pir^3xx (Q)/((4)/(3)piR^2)=(Qr^3)/(R^3)` So, electric field will be `E=(1)/(4pi epsilon_0) ((Qr^3)/(R^3))/(r^2)` ` E=(1)/(4pi epsilon_0) (Q)/(R^3).r` `rArr E prop r` (ii) When `r gt R`, Charge enclosed will be Q. So, `E=(1)/(4piepsilon_0) (Q)/(R^2)`. |
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