InterviewSolution
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InterviewSolution
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Let there be a spherically symmetric charge distribution with charge density varying as `rho(r)=rho(5/4-r/R)` upto `r=R`, and `rho(r)=0` for `rgtR`, where r is the distance from the origin. The electric field at a distance r(rltR) from the origin is given byA. ` (4 pi rho_0r)/(3varepsilon_0) (5/3 -r/R)`B. ` (4 pi rho_0r)/(3varepsilon_0) (5/3 -r/R)`C. ` (4 pi rho_0r)/(3varepsilon_0) (5/4 -r/R)`D. ` (4 pi rho_0r)/(3varepsilon_0) (5/4 -r/R)` |
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Answer» Correct Answer - B Consider a sherical shell of radius `x` and thickness dx. Charge on it dq `dq = prop xx 4 pi x^2 . Dx` ` dq = prop_0 (5/4 - x/R) xx 4 pi x^2 dx` `q = 4 pi prop _0 int_0^r ((5 x^2)/4 - x^3/R) dx` `q = 4 prop_0 ( (5r^3)/( 3 xx 4) - r^2/(4R))` `E = (kq)/r^2 = 1/( 4 pir^2) xx 4 pi prop_0 ((5r^3)/( 3xx4) - r^4/(4R))` ` E = ( prop_0r)/(4 prop_0) (5 /3 - r/R)`. |
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