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Answer: The SI unit of mutual inductance is the henry (H).
Mutual inductance is a key concept in electromagnetism that quantifies how a change in current in one coil induces an electromotive force (EMF) in a nearby coil. When the current in the first coil changes, it produces a changing magnetic field, which then induces a voltage in the second coil. The measure of this interaction is called mutual inductance, and it is measured in henry (H).
Definition of Mutual Inductance
Mutual inductance (M) is defined as the property of two coils where a change in current in one coil induces an EMF in the second coil. Mathematically, it’s given by:
Where:
- ε is the induced EMF in the second coil
- M is the mutual inductance
- dI/dt is the rate of change of current in the first coil
Why is the Unit Called Henry?
The unit henry (H) is named after Joseph Henry, an American physicist who discovered electromagnetic induction independently of Faraday. It’s the standard SI unit used to measure both self-inductance and mutual inductance.
When is Mutual Inductance Equal to One Henry?
Mutual inductance is said to be 1 henry when a change of 1 ampere per second in the current of the primary coil induces 1 volt of EMF in the secondary coil. In formula terms:
1 H=1 V/(1 A/s)
Real-World Application
Mutual inductance plays a crucial role in devices like:
- Transformers
- Inductors
- Wireless charging systems
- Electric motors
In a transformer, for example, the efficiency of energy transfer between the primary and secondary coils depends directly on their mutual inductance.
In conclusion –
🧲 Quantity Measured: Mutual Inductance (M)
📐 S.I. Unit: Henry (H)
🧪 Definition: M = 1 H when 1 A/s change in current induces 1 V in the second coil
⚡ Key Use: Transformers, inductive circuits, wireless technology
Common Doubts in Physics
