Question

How do I solve the question?Should I consider curved path AB or the straight line AB?

Answer 1

(A)

Explanation:

Length of arc `AB=Rtheta`

We know that electric field at a point is defined as the electric force per unit charge.

Work done in moving unit charge from point `A` to point `B` along the arc `AB`

`W=vecFcdot vecs=|vecE| |Rtheta|cos 0^@=ERtheta`

This is also equal to potential differential between the two points

`W=V_A-V_B`

Equating the two we get

`V_A-V_B=ERtheta`

Inserting given value of potential at `A` we get

`V-V_B=ERtheta`
`=>V_B=V-ERtheta`