Determining Charge from Charge Density

AI Thread Summary
The discussion focuses on calculating the total charge of a positively charged nonconducting solid sphere with a nonuniform volume charge density. The charge density is defined as ρ0 for r≤R/2 and 2ρ0(1−r/R) for R/2 ≤r≤R. The user attempts to solve the problem using integrals to find the charge but questions the accuracy of their calculations. Feedback indicates that the user omitted a crucial factor in their second integral, which is essential for obtaining the correct charge value. Clarification on the integral of r² is also sought, emphasizing the need for precise mathematical handling in such physics problems.
Sunbodi
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Homework Statement


A positively charged nonconducting solid sphere of radius R has a nonuniform volume charge density given by ρ0 for r≤R/2 and given by 2ρ0(1−r/R) for R/2 ≤r≤R, where r is the radial distance from the sphere center.Part A
Determine the charge q on the sphere in terms of ρ0 and R.

Homework Equations



∫ρ*dv = Q0R/2 ρ0 dVolume + R/2R ρ0 dVolume = Q from 0 to R/2 + Q from R/2 to R

The Attempt at a Solution


0R/2 ρ0 dVolume = 0R/2 ρ0 4πr2 dr
= R3πρ0/2R/2R ρ0 dVolume = R/2R ρ0 4πr2 dr

= (4R3- 3R4)*8πρ0/(12R)

Is my math wrong or is my attempt at the solution wrong? If both is wrong could you help me more with the attempt at the solution?

Thanks!

Sun

(ρ) Is rho btw.
 
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What is ∫r2.dr?

In the second integral, you left out the (1-r/R) factor.
 
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