A uniformly charged ring of radius $R$ and total charge $Q$ lies in the $xy$-plane. Find the electric field at a point $P$ on the axis at distance $x$ from the center.
A uniformly charged ring of radius $R$ and total charge $Q$ lies in the $xy$-plane. Find the electric field at a point $P$ on the axis at distance $x$ from the center.
1 Answer
VAVidaara Admin
✓ Vidaara Team
✓ Accepted
· 2mo ago
▲ 23
By symmetry, only the axial component survives:
$$E = \frac{Qx}{4\pi\epsilon_0(R^2+x^2)^{3/2}}$$
Maximum at $x = \dfrac{R}{\sqrt{2}}$:
$$E = \frac{Qx}{4\pi\epsilon_0(R^2+x^2)^{3/2}}$$
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Discussion (4)
AK
Why do we take the positive value only in the last step?
R
Underrated solution. The way you set it up makes it almost obvious.
AR
How do we know the approximation is valid here?
VA
Good follow-up questions — remember to always state your assumptions in the JEE subjective section.