Dynamo works on the principle of

Options

A. Electromagnetic induction
B. Heating effect of current
C. Chemical effect of current
D. None of these

Answer

### Step-by-Step Solution

1. **Understanding the Dynamo Structure**: A dynamo consists of a coil of wire placed within a magnetic field created by two magnets (one north pole and one south pole).

2. **Principle of Operation**: The principle of a dynamo is based on electromagnetic induction. When the coil is rotated within the magnetic field, the orientation of the coil changes with respect to the magnetic field lines.

3. **Magnetic Flux Change**: As the coil rotates, the area of the coil that is perpendicular to the magnetic field lines changes. This change in orientation leads to a change in the magnetic flux (Φ) through the coil.

4. **Faraday's Law of Electromagnetic Induction**: According to Faraday's law, a change in magnetic flux through a coil induces an electromotive force (EMF) in the coil. The induced EMF (ε) is given by the formula:
\[ \epsilon = -\frac{d\Phi}{dt} \]
where \( \frac{d\Phi}{dt} \) is the rate of change of magnetic flux.

5. **Induction of Current**: The induced EMF causes a current to flow in the coil if the circuit is closed. This flow of current is what we utilize as electrical energy.

6. **Energy Conversion**: The process involves the conversion of mechanical energy (from the rotation of the coil) into electrical energy (the current flowing in the coil).

7. **Conclusion**: Therefore, the dynamo works on the principle of electromagnetic induction, where mechanical energy is converted into electrical energy due to the change in magnetic flux through the coil.