AIIMS2018Physics-Electronics

AIIMS 2018 Physics Transistor Circuits Assertion Reason Question

Type: Assertion Reason-conceptual-Medium-Class 12

Assertion: The current gain in common base circuit is always less than one. Reason: At constant collector voltage the change in collector current is more than the change in emitter current.

A

If both assertion and reason are true and reason is the correct explanation of assertion.

B

If both assertion and reason are true but reason is not the correct explanation of assertion.

C

If assertion is true but reason is false.

D

If both assertion and reason are false.

Correct Answer

Option A

Detailed Explanation

In a common base configuration, the current gain (α) is defined as the ratio of the change in collector current (ΔI_C) to the change in emitter current (ΔI_E), and it is always less than one (α < 1) because ΔI_C is always less than ΔI_E due to the transistor's operation. The reason provided is true as it correctly states that at a constant collector voltage, the change in collector current is less than the change in emitter current, thus supporting the assertion. Options B, C, and D are incorrect because they either misinterpret the relationship between collector and emitter currents or incorrectly assert the truth of one or both statements.

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