To solve the problem, we need to analyze the assertion (A) and the reason (R) given in the question.
**Assertion (A):** When a body is charged, its mass changes.
**Reason (R):** Charge is quantized.
### Step-by-Step Solution:
1. **Understanding the Assertion (A):**
- When a body is charged, it either gains or loses electrons.
- Electrons have mass, approximately \(9.11 \times 10^{-31}\) kg.
- Therefore, if electrons are added to a body (making it negatively charged), the mass of the body will increase.
- Conversely, if electrons are removed (making it positively charged), the mass of the body will decrease.
- Thus, the assertion that "when a body is charged, its mass changes" is true.
2. **Understanding the Reason (R):**
- The reason states that "charge is quantized."
- This means that charge exists in discrete amounts, typically in multiples of the elementary charge \(e\) (where \(e = 1.6 \times 10^{-19}\) coulombs).
- While it is true that charge is quantized, this fact does not directly explain why the mass of the body changes when it is charged.
- The mass change occurs due to the addition or removal of electrons, not solely because charge is quantized.
3. **Conclusion:**
- Both the assertion and the reason are correct statements.
- However, the reason does not correctly explain the assertion. The assertion is about mass change due to the addition or removal of electrons, while the reason discusses the quantization of charge, which is not directly related to the mass change.
- Therefore, the correct answer is that both statements are true, but the reason is not the correct explanation for the assertion.
### Final Answer:
Both assertion and reason are correct, but the reason is not the correct explanation for the assertion.
