Determining Charge from Charge Density

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SUMMARY

The discussion focuses on calculating the total charge \( q \) of a positively charged nonconducting solid sphere with a nonuniform volume charge density defined as \( \rho_0 \) for \( r \leq R/2 \) and \( 2\rho_0(1 - r/R) \) for \( R/2 \leq r \leq R \). The charge is determined using the integral \( Q = \int \rho \, dv \), which is split into two parts: \( Q_1 \) for \( r \leq R/2 \) and \( Q_2 \) for \( R/2 \leq r \leq R \). The user seeks clarification on their calculations, specifically regarding the integration process and the inclusion of the charge density factor in the second integral.

PREREQUISITES
  • Understanding of electrostatics and charge density concepts
  • Familiarity with integral calculus, particularly volume integrals
  • Knowledge of spherical coordinates and their application in physics
  • Experience with nonuniform charge distributions in electrostatics
NEXT STEPS
  • Review the derivation of charge density equations in electrostatics
  • Study the application of spherical coordinates in volume integrals
  • Learn about the implications of nonuniform charge distributions on electric fields
  • Practice solving similar problems involving charge density and integration techniques
USEFUL FOR

This discussion is beneficial for physics students, educators, and anyone involved in electrostatics, particularly those dealing with charge distributions and integral calculus in their studies or research.

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.
 
Physics news on Phys.org
What is ∫r2.dr?

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

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