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Statement-1: Potassium and caesium are u...

Statement-1: Potassium and caesium are used in photo-electric cells.
Statement-2: Potassium and caesium emit electrons on exposure to light above certain minimum frequency.

A

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

B

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

C

If the assertion is true but the reason is false.

D

If both assertion and reason are false.

Text Solution

Verified by Experts

The correct Answer is:
A
The valence shell electron in the alkali metals is so loosely held that even the low energy photons ( light) can eject this electron from the metal surface. This phenomenon is called as photoelectric effect , K and Cs are used in photoelectric cells which are sensitive to blue light.
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