Key relationship
E⃗ = Σ k qⱼ r⃗ⱼ/rⱼ³; Ering = kQx/(a²+x²)³ᐟ².
Physics · Class 12
Superposition and charged ring
Point-charge vectors add component by component. A uniformly charged ring is the continuous limit: transverse components cancel on its axis. Select both sources to compare.
Open the interactive experiment →Superposition and charged ring
பல மின்னூட்டங்களின் மின்புலங்கள் திசையன்களாகக் கூடுகின்றன. வளையத்தின் அச்சில் குறுக்கு கூறுகள் ரத்தாகும்.
Key notes, relationships and model limits
Remember
Point-charge vectors add component by component. A uniformly charged ring is the continuous limit: transverse components cancel on its axis. Select both sources to compare.
Common trap
Add electric-field components as vectors. Adding only their magnitudes misses cancellation and direction.
Model limits
Ring has uniform line charge. Point probes retain positive height to avoid charge singularities.
What you will learn
Use the controls and plotted relation to explain superposition and charged ring.
Try the experiment
Try both scenarios, change one control, and predict the result before checking the graph and readouts.
Think of it this way
Change one input while keeping the others fixed, as you would in a controlled experiment.
Worked example
A 2 µC ring of radius 0.5 m has E=0 at its centre, though its potential is kQ/a≈35,950 V.
Why this matters
The model connects superposition and charged ring with an observable reading. Check the equation and assumptions before applying it.
Before you start
SI units · algebra · graph reading
Check your understanding
At the centre of a uniformly charged ring, what is the electric field?
- It is maximum because every charge element is positive.
- It is zero because opposite elements cancel.
- It is nonzero and always points along the ring plane.
Read the explanation
It is zero because opposite elements cancel.
Course connection: Class XII Chapter 1. Consult the roadmap for CBSE, NEET, JEE Main and Advanced scope.