Chapter 21, Problem 1CQ

To determine

The potential at point $B$ if a $20\text{}\text{nC}$ charge is moved from the point $A$ to $B$.

Answer to Problem 1CQ

The potential at the point is $150\text{ Volt}$.

Explanation of Solution

Electric potential at a point is defined as the work done in moving a point charge from infinity to that point. It can also be defined as the electric potential energy per unit charge.

Electric potential at a point doesn’t depend on the test charge used whereas it depends on the source of the potential. Only the work done in moving a charge depends on the test charge. If the test charge is doubled, then work done is also doubled, however potential remains the same.

Thus, the potential at point $B$ will remain same irrespective of the charge used to measure it.

Conclusion:

Potential at a point doesn’t depend on the test charge used. Thus, the potential at the point is $150\text{ Volt}$.