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Passage-I : Two large plates are locat...

Passage-I :
Two large plates are located in vacuum. One of them serves as a cathode, a source of electrons whose initial velocity is negligible. An electron flow directed toward the opposite plate produces a space charge causing the potential in the gap between the plates to vary as `V=ax^(4//3)`, where a is a positive constant, and x is the distance from the cathode.

The current density

A

`-(2)/(3) in_(0)a^(3//2) sqrt((2e)/(m))`

B

`-(4)/(9) in_(0)a^(3//2)sqrt((2e)/(m))`

C

`-(2)/(3)in_(0)a^(3//2)sqrt((2e)/(m))`

D

None.

Text Solution

Verified by Experts

The correct Answer is:
B
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