(A): Gamma rays are more energetic than X-rays (R) : Gamma rays are of nuclear origin but X-rays are produced due to sudden deceleration of high energy electron while falling on a metal of high atomic number

Options

A. Both 'A' and 'R' are true and 'R' is the correct explanation of 'A'.
B. Both 'A' and ’R' are true and 'R' is not the correct explanation of 'A
C. A' is true and 'R' is false
D. 'A' is false and R' is true

Answer

To solve the question regarding the assertion (A) and reason (R) about gamma rays and X-rays, we will analyze both statements step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Gamma rays are more energetic than X-rays."
- This is based on the fact that gamma rays have a higher frequency than X-rays. In the electromagnetic spectrum, energy is directly proportional to frequency (E = hν, where E is energy, h is Planck's constant, and ν is frequency). Therefore, if gamma rays have a higher frequency, they must also have more energy.

2. **Understanding the Reason (R)**:
- The reason states that "Gamma rays are of nuclear origin but X-rays are produced due to sudden deceleration of high energy electrons while falling on a metal of high atomic number."
- This statement is true. Gamma rays are indeed produced during nuclear reactions (e.g., radioactive decay), while X-rays are produced when high-energy electrons collide with a metal target, causing the electrons to decelerate and emit energy in the form of X-rays.

3. **Analyzing the Relationship Between A and R**:
- Both the assertion and the reason are true statements. However, we need to determine if the reason correctly explains the assertion.
- The reason describes the origins of gamma rays and X-rays, but it does not directly explain why gamma rays are more energetic than X-rays. The explanation of energy levels and frequency is not provided in the reason.

4. **Conclusion**:
- The assertion (A) is true: Gamma rays are indeed more energetic than X-rays.
- The reason (R) is also true: Gamma rays originate from nuclear processes, while X-rays are produced from high-energy electron interactions.
- However, the reason does not adequately explain the assertion, as it lacks the necessary information about the relationship between frequency and energy.

### Final Answer:
- The assertion (A) is true, and the reason (R) is true, but the reason does not explain the assertion. Thus, the correct choice would be that both A and R are true, but R is not the correct explanation for A.