Published by:
CGP EDU Academic Team
Published on: September 12, 2026
A negatively charged plate has charge density of
. The initial distance of an electron which is moving toward plate, cannot strike the plate, if it is having energy of 
Text Solution
Verified by ExpertsThe correct answer is:
A
Let an electron is projected towards the plate from the r distance as shown in fig.

It will not strike the plate if and only if KE ≤ ≤ e(E ⋅ ⋅ r) (where E = Electric field due to charge plate
)
⇒ ⇒
. Hence minimum value of r is given by

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