Question
For question two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions front the codes (a), (b), (c) and (d) as given below.
  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is NOT the correct explanation of A.
  3. A is true but R is false.
  4. A is false and R is also false.
Assertion (A): ln photoemissive cell inert gas is used.
Reason (R): Inert gas in the photoemissive cell gives greater current.

Answer

  1. Both A and R are true and R is the correct explanation of A.
Explanation:
The photoemissive cell contain two electrodes are enclosed in a glass bulb which may be evacuated or contain an inert gas at low pressure. An inert gas in the cell gives greater current but causes a time lag in the response of the cell to very rapid changes ofradiation which may make it unsuitable for some purpose.

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Assertion: The dominant mechanism for motion of charge carriers in forward and reverse biase silicon p-n junction are drift in both forward and reverse bias.
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Assertion: The light travelling from air to glass can not suffer total internal reflection.
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Assertion: Optical fibers are used to transmit light without any loss in its intensity over distance of several kilometers.
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