Question

Potential at a point $A$ is $3$ $volt$ and at a point $B$ is $7$ $volt$, an electron is moving towards $A$ from $B$.

• A. It must have some $K.E$ at $B$ to reach $A$
• B. It need not have any $K.E$ at $B$ to reach $A$
• C. to reach $A$ it must have more than or equal to $4eV$ $K.E$. at $B$
• D. when it will reach $A$, it will have $K.E.$ more than or atleast equal to $4eV$ if it was released from rest at $B$

Answer 1

Answer: (A), (C)

to reach $A$ it must have more than or equal to $4eV$ $K.E$. at $B$
It must have some $K.E$ at $B$ to reach $A$

Here some kinetic energy must be needed to reach B to A because electron is moving.
$KE=qV=e(7-3)V=4eV$
As the electron is moving towards A from B so the KE must have equal or greater $4eV$ KE at B to reach A.