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Hi guys,

I am stuck at this problem,

Here it is given that an insulating sphere of radius a, carries a charge density ρ=ρ'( a^2-r^2)cosθ, when r <a. How will the leading order term for the electric field at a distance d, far away from this charge distribution vary?

ρ' is a constant term.

I was thinking of calculating the total charge first. But here on integrating the given charge density I'm ending up getting zero.

∫ρ dτ= 0. Because dτ=r^2 sinθ dθ dφ dr

I'm unable to understand how to approach the sum, if I'm getting the total charge 0 in the first place????

The answer is that the field must vary by d^-1

Hi guys,

I am stuck at this problem,

## Homework Statement

Here it is given that an insulating sphere of radius a, carries a charge density ρ=ρ'( a^2-r^2)cosθ, when r <a. How will the leading order term for the electric field at a distance d, far away from this charge distribution vary?

ρ' is a constant term.

## Homework Equations

## The Attempt at a Solution

[/B]I was thinking of calculating the total charge first. But here on integrating the given charge density I'm ending up getting zero.

∫ρ dτ= 0. Because dτ=r^2 sinθ dθ dφ dr

I'm unable to understand how to approach the sum, if I'm getting the total charge 0 in the first place????

The answer is that the field must vary by d^-1

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