Assertion : When there is a thin layer of water between two glass plates , there is a strong attraction between them .
Reason : The pressure between the plate becomes less than atmospheric pressure because pressure inside a bubble or drop is greater than outside pressure.

Options

A. Assertion is true , Reason is true, Reason is correct explanation for Assertion .
B. Assertion is true , reason Is true, Reason is not a correct explanation for Assertion .
C. Assertion is true , reason is false
D. Assertion is false ,reason is true

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Analyze the Assertion
The assertion states: "When there is a thin layer of water between two glass plates, there is a strong attraction between them."

- When two glass plates are placed with a thin layer of water in between, the water creates a meniscus effect due to surface tension.
- This surface tension causes the water molecules to adhere to the glass, creating a cohesive force that pulls the plates together.
- Therefore, the assertion is **true**.

### Step 2: Analyze the Reason
The reason states: "The pressure between the plates becomes less than atmospheric pressure because pressure inside a bubble or drop is greater than outside pressure."

- When two plates are close together with a thin layer of water, the pressure in the water layer can indeed be less than atmospheric pressure due to the curvature of the water surface (like in a drop or bubble).
- The pressure difference is explained by the Young-Laplace equation, which states that the pressure inside a curved surface (like a drop) is greater than the pressure outside.
- This creates a situation where the pressure between the plates is lower than atmospheric pressure, leading to an attractive force between the plates.
- Therefore, the reason is also **true**.

### Step 3: Conclusion
Both the assertion and the reason are true, and the reason correctly explains the assertion. Thus, the correct option is:

- **Option A: Both assertion and reason are true, and the reason is the correct explanation for the assertion.**