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A rod of length L has a charge Q uniformly distributed along its length. The rod lies along the y axis with one end at the origin. (a) Find
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A rod of length L has a charge Q uniformly distributed along its length. The rod lies along the y axis with one end at the origin. (a) Find an expression for the electric potential as a function of position along the x axis.
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Physics
3 years
2021-08-22T01:19:41+00:00
2021-08-22T01:19:41+00:00 1 Answers
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Answer:
V = k Q/l ln [(l +√(l² + x²)) / x]
Explanation:
The electrical potential for a continuous distribution of charges is
V = k ∫ dq / r
Let’s apply this expression to our case, define a linear charge density for the bar
λ = dq / dy
dq = λ dy
The distance from a point on the bar to the x-axis is
r = √ (x² + y²)
Let’s replace
V = K ∫ λ dy /√ (x² + y²)
We integrate
V = k λ ln (y + √ (x² + y²))
Let’s evaluate between y = 0 and y = l
V = k λ [ ln (l +√(x² + l²) – ln x]
We substitute the linear density
V = k Q/l ln [(l +√(l² + x²)) / x]