The direction of induced e.m.f. during electromagnetic induction is given by

Options

A. Faraday's law
B. Lenz's law
C. Maxwell's law
D. Ampere's law

Answer

To determine the direction of induced electromotive force (e.m.f.) during electromagnetic induction, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Electromagnetic Induction**:
- Electromagnetic induction occurs when a change in magnetic flux through a coil induces an electromotive force (e.m.f.) in that coil.

2. **Faraday's Law of Induction**:
- According to Faraday's Law, the induced e.m.f. (ε) in a coil is proportional to the rate of change of magnetic flux (Φ) through the coil:
\[ \epsilon = -\frac{d\Phi}{dt} \]
- The negative sign indicates the direction of the induced e.m.f.

3. **Lenz's Law**:
- Lenz's Law provides the direction of the induced e.m.f. It states that the induced current will flow in a direction that opposes the change in magnetic flux that produced it.
- If the magnetic flux through the coil is increasing, the induced current will flow in a direction that creates a magnetic field opposing the increase.
- Conversely, if the magnetic flux is decreasing, the induced current will flow in a direction that attempts to maintain the magnetic flux by opposing the decrease.

4. **Application of Lenz's Law**:
- To apply Lenz's Law, determine whether the magnetic flux is increasing or decreasing.
- If the flux is increasing, the induced current will flow in a direction that opposes this increase.
- If the flux is decreasing, the induced current will flow in a direction that opposes the decrease.

5. **Conclusion**:
- Therefore, the direction of the induced e.m.f. is determined by Lenz's Law, which states that the induced e.m.f. will always act to oppose the change in magnetic flux.

### Final Answer:
The direction of induced e.m.f. during electromagnetic induction is given by Lenz's Law.

---