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Electronic Devices and Circuits - Engineering

Q1:

Assertion (A): Oxide coated cathodes are very commonly used. Reason (R): Work function of oxide coated cathode is 1 eV whereas it is 4.5 eV for pure tungsten.

A Both A and R are true and R is correct explanation of A

B Both A and R are true but R is not a correct explanation of A

C A is true but R is false

D A is false but R is true

ANS:A - Both A and R are true and R is correct explanation of A

Lower work function leads to higher emission current. Therefore oxide coated cathodes are commonly used.