How Do You Calculate Charge Density in a Uniform Sphere?

In summary, the charge density in a nonconducting sphere of radius ##R## with a uniformly distributed charge ##Q## is ρ=Q/(4/3ϖr^3). There is no need to use Gauss's Law in this case.
  • #1
TishBass
3
0

Homework Statement


A charge Q is uniformly distributed throughout a nonconducting sphere of radius R. Write the expression of the charge density in the sphere?

Homework Equations


Charge density ρ=dQ/dV
Gauss's Law ∫EdA = E(4ϖr^2)

The Attempt at a Solution


If Q is uniform then ρ=Q/dV and the volume of a sphere is 4/3ϖr^3 then I think charge density would just be ρ=Q/(4/3ϖr^3).
This is suspiciously simple so I would just like external input on the problem. I have a feeling that I may need to use Gauss's Law somehow.
 
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  • #2
TishBass said:

Homework Statement


A charge Q is uniformly distributed throughout a nonconducting sphere of radius R. Write the expression of the charge density in the sphere?

Homework Equations


Charge density ρ=dQ/dV
Gauss's Law ∫EdA = E(4ϖr^2)

The Attempt at a Solution


If Q is uniform then ρ=Q/dV and the volume of a sphere is 4/3ϖr^3 then I think charge density would just be ρ=Q/(4/3ϖr^3).
This is suspiciously simple so I would just like external input on the problem. I have a feeling that I may need to use Gauss's Law somehow.

That's all there is to it. ##Q## could be anything uniformly distributed across volume ##V## and the density is, by definition, ##Q/V##.
 

1. What is charge density expression?

Charge density expression refers to the mathematical representation of the distribution of electric charge in a given system. It is defined as the amount of charge per unit volume at a specific point in space.

2. How is charge density expression calculated?

The charge density expression is calculated by dividing the total charge of a system by its volume. This can be represented as ρ = Q/V, where ρ is the charge density, Q is the total charge, and V is the volume.

3. What units are used to express charge density?

Charge density is typically expressed in units of coulombs per cubic meter (C/m³) in the SI system. In the CGS system, it is expressed in units of coulombs per cubic centimeter (C/cm³).

4. How is charge density related to electric field?

Charge density is directly related to the strength of the electric field in a given system. The electric field is proportional to the charge density at a specific point in space, with a higher charge density resulting in a stronger electric field.

5. Why is charge density expression important in scientific research?

Charge density expression is important in scientific research because it helps us understand the behavior of electrically charged particles and their interactions with each other. It is also used in various fields such as electrochemistry, materials science, and solid-state physics to study the properties of materials and their electrical conductivity.

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