Assertion: In reverse biased condition a p-n junction diode does not conduct.
Reason: In reverse biased condition a diode has zero resistance.

Answer

To solve the question, we need to analyze the assertion and the reason given for the behavior of a p-n junction diode in reverse bias.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "In reverse biased condition, a p-n junction diode does not conduct."
- In reverse bias, the p-type is connected to the negative terminal and the n-type is connected to the positive terminal. This increases the potential barrier at the junction, preventing current flow. Therefore, the assertion is **true**.

2. **Understanding the Reason**:
- The reason states that "In reverse biased condition, a diode has zero resistance."
- While it is true that the diode does not conduct significant current in reverse bias, it does not mean that it has zero resistance. There is still a small amount of reverse saturation current that flows due to minority carriers, and the diode exhibits some resistance. Thus, the reason is **false**.

3. **Conclusion**:
- Since the assertion is true and the reason is false, we conclude that the correct answer is: **Assertion is true but reason is false**.

### Final Answer:
- Assertion: True
- Reason: False
- Conclusion: Assertion is true but reason is false.

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