When interference of light takes place

Options

A. energy is created in the region of maximum intensity
B. energy is distroyed in the region of maximum intensity
C. conservation of energy holds good and energy is redistributed
D. conservation of energy does not hold good

Answer

To answer the question "When does interference of light take place?" we will break down the concept of light interference step by step.

### Step-by-Step Solution:

1. **Understanding Interference**:
Interference of light occurs when two or more light waves overlap and combine. This can happen when light from different sources (like lasers) or different parts of the same wavefront (like in a double-slit experiment) meet.

**Hint**: Think of waves in water; when two waves meet, they can either amplify each other (constructive interference) or cancel each other out (destructive interference).

2. **Conditions for Interference**:
For interference to occur, the following conditions must be met:
- The light waves must be coherent, meaning they have a constant phase difference and the same frequency.
- The waves should overlap in space, which usually happens in setups like Young's double-slit experiment.

**Hint**: Coherence is like having two musicians playing the same tune in sync; if they are out of sync, the harmony is lost.

3. **Constructive and Destructive Interference**:
- **Constructive Interference** occurs when the waves are in phase (their peaks align), resulting in increased intensity (bright fringes).
- **Destructive Interference** occurs when the waves are out of phase (the peak of one wave aligns with the trough of another), resulting in decreased intensity (dark fringes).

**Hint**: Visualize a seesaw; when both sides go up together, it’s constructive (up), and when one goes up while the other goes down, it’s destructive (down).

4. **Intensity Calculation**:
The intensity of the resultant wave can be calculated based on the amplitudes of the individual waves. For two waves of amplitude \( A \):
- Maximum intensity \( I_{max} = 4A^2 \) (constructive interference)
- Minimum intensity \( I_{min} = 0 \) (destructive interference)

**Hint**: Remember that intensity is proportional to the square of the amplitude. This is like how a small increase in volume can lead to a big change in sound intensity.

5. **Energy Redistribution**:
In regions of maximum intensity, energy is not created; it is redistributed from regions of minimum intensity. This means that while some areas become brighter, others become darker, but the total energy remains constant.

**Hint**: Think of energy like water in a tank; if you pour water into one section, it has to come from somewhere else.

### Conclusion:
Interference of light takes place when coherent light waves overlap, leading to regions of constructive and destructive interference, resulting in a pattern of light and dark fringes. The energy is conserved and redistributed between these regions.