In Young's double slit experiment the type of diffractive is

Options

A. Fresnel
B. Fraunhofer
C. Both (a) and (b)
D. None of these

Answer

To solve the question regarding the type of diffraction in Young's double slit experiment, we can break it down into the following steps:

### Step 1: Understanding Young's Double Slit Experiment
Young's double slit experiment involves a coherent light source illuminating two closely spaced slits, which then creates an interference pattern on a screen. The light waves from the two slits overlap and interfere with each other.

**Hint:** Recall the basic setup of Young's double slit experiment, including the light source, slits, and screen.

### Step 2: Identifying Types of Diffraction
There are two main types of diffraction:
- **Fresnel Diffraction**: Occurs when the source and the screen are at finite distances from the obstacle (or slit). This type of diffraction is observed in situations where the wavefronts are not parallel.
- **Fraunhofer Diffraction**: Occurs when the source and the screen are at infinite distances from the obstacle. In this case, the wavefronts can be considered parallel.

**Hint:** Differentiate between Fresnel and Fraunhofer diffraction based on the distances involved.

### Step 3: Analyzing the Conditions of the Experiment
In Young's double slit experiment, the light source and the screen are at finite distances. This means that the light waves are not parallel when they reach the screen, which is characteristic of Fresnel diffraction.

**Hint:** Consider the arrangement of the source, slits, and screen in the context of the type of diffraction.

### Step 4: Conclusion
Since the conditions of Young's double slit experiment match the criteria for Fresnel diffraction, we conclude that the type of diffraction observed in this experiment is Fresnel diffraction.

**Hint:** Reflect on the definitions of Fresnel and Fraunhofer diffraction and how they apply to the experiment.

### Final Answer
The type of diffraction in Young's double slit experiment is **Fresnel diffraction**.