Assertion : In common base configuration, the current gain of the transistor is less than unity.
Reason : The collector terminal is revers biased for amplification.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion.
B. if both assertion and reason are true but reason is not the correct expalanation of the assertion
C. if assertion is true , but reason is false
D. both assertion and reason are false statements.

Explanation

To analyze the given assertion and reason, let's break down the statements step by step.

### Step 1: Understanding the Assertion
**Assertion:** In common base configuration, the current gain of the transistor is less than unity.

- In a common base (CB) configuration, the transistor operates with the base terminal common to both the input and output circuits.
- The current gain (α) in this configuration is defined as the ratio of the output current (collector current, Ic) to the input current (emitter current, Ie).

\[ \alpha = \frac{I_c}{I_e} \]

- In a common base configuration, it is known that the collector current (Ic) is always less than the emitter current (Ie) because some current flows into the base (Ib). Therefore, the current gain α is less than 1 (or unity).

### Step 2: Understanding the Reason
**Reason:** The collector terminal is reverse biased for amplification.

- In the common base configuration, the collector-base junction is indeed reverse biased. This is essential for the transistor to operate in the active region and to amplify the signal.
- The reverse biasing of the collector-base junction allows for a higher collector current, which is necessary for amplification.

### Step 3: Conclusion
- Both the assertion and the reason are true statements.
- However, the reason does not directly explain the assertion. The assertion talks about the current gain being less than unity, while the reason discusses the reverse biasing of the collector terminal, which is a characteristic of the configuration but does not explain why the current gain is less than unity.

### Final Answer
Both the assertion and the reason are true, but the reason is not the correct explanation for the assertion. Therefore, the correct option is that both statements are true, but the reason is not the correct explanation.