Assertion : Alpha particles produce more intense ionisation than beta particles.
Reason : Alpha particles are positively charged .

Options

A. If both the assertion and reason are true statement and reason is correct explanation of the assertion .
B. If both the assertion and reason are true statement but reason is not a correct explanation of the assertion .
C. If the assertion is true but the reason is a false statement.
D. If both assertion and reason are false statements.

Explanation

To solve the question regarding the assertion and reason about alpha and beta particles, we can break it down step by step:

### Step 1: Understand the Assertion
The assertion states that "Alpha particles produce more intense ionization than beta particles."

- **Explanation**: Alpha particles are helium nuclei, which consist of 2 protons and 2 neutrons. They are relatively large and carry a double positive charge. Due to their size and charge, they can cause significant ionization as they pass through matter.

### Step 2: Understand the Reason
The reason given is "Alpha particles are positively charged."

- **Explanation**: Alpha particles indeed carry a positive charge (specifically, a charge of +2e). This charge contributes to their ability to ionize atoms effectively as they interact with them.

### Step 3: Compare Ionization Capabilities
Now, we need to compare the ionization capabilities of alpha and beta particles.

- **Alpha Particles**:
- Large mass
- Double positive charge
- Lower velocity
- High ionization capacity due to strong interactions with matter.

- **Beta Particles**:
- Much smaller mass (essentially negligible compared to alpha)
- Single negative charge (for electrons) or positive charge (for positrons)
- High velocity
- Lower ionization capacity as they pass through matter because they interact less strongly.

### Step 4: Conclusion
From the above analysis, we conclude that:
- The assertion is true: Alpha particles do produce more intense ionization than beta particles.
- The reason is also true: Alpha particles are positively charged.
- However, the reason provided does not adequately explain why alpha particles produce more intense ionization than beta particles, as it does not consider the size and mass of the particles.

### Final Answer
Thus, the correct conclusion is that both the assertion and reason are true, but the reason is not the correct explanation for the assertion. Therefore, the answer is option B.

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