Assertion : In a radioactive disintegration, an electron is emitted by the nucleus.
Reason : Electrons are always present inside the nucleus.

Options

A. Both Assertion and Reason are true and Reason is the correct explanation of Assertion
B. Both Assertion and Reason are true but Reason is not a correct explanation of Assertion
C. Assertion is true but Reason is false
D. Assertion is false but Reason is true

Answer

To solve the given question, we need to analyze the assertion and reason provided:

**Assertion:** In a radioactive disintegration, an electron is emitted by the nucleus.
**Reason:** Electrons are always present inside the nucleus.

### Step-by-Step Solution:

1. **Understanding Radioactive Disintegration:**
- Radioactive disintegration refers to the process by which an unstable atomic nucleus loses energy by emitting radiation. This can include alpha particles, beta particles (which are electrons), and gamma rays.

2. **Analyzing the Assertion:**
- In beta decay (specifically beta minus decay), a neutron in the nucleus is transformed into a proton, and in this process, an electron (beta particle) is emitted. Therefore, the assertion that "an electron is emitted by the nucleus" is **true**.

3. **Analyzing the Reason:**
- The reason states that "electrons are always present inside the nucleus." This is **false**. The nucleus is composed of protons and neutrons. Electrons are found in the electron cloud surrounding the nucleus, not inside it.

4. **Conclusion:**
- Since the assertion is true and the reason is false, we conclude that the correct option is that the assertion is true, but the reason is false.

### Final Answer:
The assertion is true, and the reason is false. The correct option is that the assertion is true, but the reason is false.

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