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Grade 12Electrostatics

sir,

in AIEEE ,there was aquwstion regarding electric field and i have some doubt during solving it...plz help me in this question.It goes as...

Let there be a spherically symmetric charge distribution with charge density varying as Rho(r)=Rho -not (5/4 -r/R) & rho(r)=0 for r>R,where r is the distance from the origin.The electric field at a distance r(r

1.rho_not r/3Eo(5/4 -r/R)

2.4pie rho -notr /3Eo (5/4 -r/R)

3.rho-not r/4Eo (5/4 -r/R )

4.4Rho-not r/3Eo (5/4-r/R)

when i attempted it .my ans was wrong,then aftewr it on seeing its solution ,he has taken dq=rho* 4 pie r square but i have doubt it should be dq=rho *4/3 pie r cube.....becoz it is the volume charge density...plz HELP ME

Profile image of syed obaid
15 Years agoGrade 12
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1 Answer

Profile image of vikas askiitian expert
15 Years ago

dq = 4/3 pir3 when charge distribution does not depend on radial distance , if dencity is uniform everywhere inside the sphere then this is true otherwise

dq = po(function of r)(4pir2)dr

4pir2dr is volume in this case