A: bohr's orbits are also called stationary states
R : Electrons are stationary in an orbit .

Options

A. IF both assertion & reason are true and the reason is the correct explanation of the assertion then mark
B. IF both assertion & reason are true but the reason is not the correct explanation of the assertion , then mark
C. IF assertion is true statement but reason is false , then mark
D. If both assertion and reason are false statements then mark

Answer

To solve the question regarding the assertion and reason about Bohr's orbits, we will analyze both statements step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Bohr's orbits are also called stationary states."
- This is based on Bohr's model of the atom where electrons revolve around the nucleus in specific orbits without radiating energy.

2. **Evaluating the Assertion**:
- According to Bohr's theory, these orbits are termed "stationary states" because electrons in these orbits do not lose energy as they move.
- If they were to lose energy, they would spiral into the nucleus, leading to the collapse of the atom.
- Therefore, this assertion is **true**.

3. **Understanding the Reason**:
- The reason states that "Electrons are stationary in an orbit."
- This implies that electrons do not move within these orbits.

4. **Evaluating the Reason**:
- This statement is **false**. While the orbits are called stationary states, it does not mean that the electrons are stationary.
- Electrons are in constant motion within these orbits; they do not lose energy while moving in their defined paths.

5. **Conclusion**:
- Since the assertion is true and the reason is false, the correct conclusion is that the assertion is valid, but the reason provided is incorrect.

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