**Potential Difference Numerical problems** – In this post, we will solve selected numerical problems on Potential Difference (PD). To solve these PD numericals we will use concepts and formulas of *electric potential* and *PD*.

## Potential Difference Numericals – with solution

### 1 ) A 500μC charge is at the centre of a square of side 10 cm. Find the work done in moving a charge of 10μC between two diagonally opposite points on the square.

**Solution:**

**Step 1: Electric Potential at points A and B**

The formula of Electric potential V=kQ/r

The source charge (500μC) is located at the centre of a square. (see figure 1) We know, that the centre of a square can be located at that point where its diagonals cross each other.

In figure 1 above we have shown points A and B as two diagonally opposite points on the square.

Since, Points A and B are equidistant from the centre of the square where charge q=500μC is located, therefore, points A and B are at the same potential i.e., V_{A}=V_{B}

**Step 2: Work done**

∴ Work done by an external agent in moving charge q_{O} =10μC from A to B will be

W = qΔV = q_{0} (V_{B}−V_{A}) =10 x 0 = 0

Hence, the Work done in moving the charge from A to B will be zero.

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