Question

Charges are placed on the vertices of a square as shown. Let $\overrightarrow{E}$ be the electric field and V the potential at the centre. If the charges on A and B are interchanged with those on D and C respectively, then [AIEEE-2007]

• A. Both $\overrightarrow{E}$ and V change
• B. $\overrightarrow{E}$ and V remain unchanged
• C. $\overrightarrow{E}$ changes, V remains unchanged
• D. $\overrightarrow{E}$ remains unchanged, V changes

Answer 1

The correct option is C $\overrightarrow{E}$ changes, V remains unchanged

If charges are interchanged, the separation of charges remains unchanged from the centre of the square. Thus potential won't change as it is a scalar quantity.

Although the Electric field will now point in the opposite direction i.e., upwards without any change in its magnitude. Electric field is a vector quantity and points radially away from positive charges.