Key relationship
F=−cv; c=geometry·B²/R; v=v₀ exp(−ct/m).
Physics · Class 12
Eddy-current magnetic braking
A moving conductor develops eddy currents that resist motion. This effective-loop model shows increased braking with stronger field and smaller loop resistance.
Open the interactive experiment →Eddy-current magnetic braking
நகரும் கடத்தியில் சுழல் மின்னோட்டங்கள் இயக்கத்தை எதிர்க்கின்றன. இயக்க ஆற்றல் வெப்பமாக மாறும்.
Key notes, relationships and model limits
Remember
A moving conductor develops eddy currents that resist motion. This effective-loop model shows increased braking with stronger field and smaller loop resistance.
Common trap
Magnetic braking converts kinetic energy into heat in induced currents; the damping coefficient here is a geometry-dependent approximation.
Model limits
Lumped effective eddy loops, linear magnetic drag and constant B; excludes skin effect and detailed plate geometry.
What you will learn
Use the controls and plotted relation to explain eddy-current magnetic braking.
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
With geometry=2 m², B=0.5 T and R=1 Ω, c=0.5 kg/s; a 1 kg plate retains e⁻¹ of its speed after 2 s.
Why this matters
The model connects eddy-current magnetic braking with an observable reading. Check the equation and assumptions before applying it.
Before you start
SI units · algebra · graph reading
Check your understanding
Stronger B in this eddy-current braking model gives?
- Less braking because current is blocked by B.
- More braking because damping is proportional to B².
- The same braking because speed alone matters.
Read the explanation
More braking because damping is proportional to B².
Course connection: Class XII Chapter 6. Consult the roadmap for CBSE, NEET, JEE Main and Advanced scope.