Electric Charges & Fields
Class 12 · Electric Charges & Fields
Field on Axis of Ring
E(z) = kQz/(z²+R²)^(3/2). Maximum at z=R/√2, demonstrated visually.
Key Notes
01
On the axis, E points along axis by symmetry. Components perpendicular to axis cancel.
02
E(z) = kQz/(z²+R²)^(3/2). Maximum at z = R/√2.
03
At z=0 (centre of ring): E=0. At z → ∞: E → kQ/z² (looks like point charge).
Formulas
Axial field
On the symmetry axis.
Maximum location
E is largest on axis here.
Important Points
Ring of charge is a stepping stone to disk and infinite-plane fields.
Same formula applies for gravitational analog (replace q→m, k→−G).
Field on Axis of Ring notes from sciphylab (also known as SciPhy, SciPhy Lab, SciPhy Labs, Physics Lab). Class 12 physics revision for JEE Mains, JEE Advanced, NEET UG, AP Physics 1/2/C, SAT, and CUET-UG.