Key relationship
Φ=BA cosθ; ε=−N dΦ/dt=−NA cosθ dB/dt.
Physics · Class 12
Faraday flux and induced EMF
Hold coil geometry fixed and vary the rate of field change. A large but steady field gives zero EMF; changing field creates an induced voltage.
Open the interactive experiment →Faraday flux and induced EMF
காந்தப்பாயம் மாறும்போது தூண்டிய EMF உருவாகும். நிலையான காந்தப்புலம் மட்டும் EMF உருவாக்காது.
Key notes, relationships and model limits
Remember
Hold coil geometry fixed and vary the rate of field change. A large but steady field gives zero EMF; changing field creates an induced voltage.
Common trap
EMF depends on the rate of flux change, not simply on the size of the flux at one instant.
Model limits
Uniform field, fixed coil area and orientation; no self-induction or coil capacitance.
What you will learn
Use the controls and plotted relation to explain faraday flux and induced emf.
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 N=100, A=100 cm² and dB/dt=0.5 T/s at θ=0°, ε=−0.5 V.
Why this matters
The model connects faraday flux and induced emf with an observable reading. Check the equation and assumptions before applying it.
Before you start
SI units · algebra · graph reading
Check your understanding
A stationary coil in a constant B has induced EMF?
- NBA even when B is steady.
- Zero because its magnetic flux is unchanged.
- A nonzero EMF proportional to the steady B alone.
Read the explanation
Zero because its magnetic flux is unchanged.
Course connection: Class XII Chapter 6. Consult the roadmap for CBSE, NEET, JEE Main and Advanced scope.