#### Charges are placed on the vertices of a square as shown. Let 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 espectively, then Option 1) changes,V remains unchanged Option 2) remains unchanged V changes Option 3) both and V change Option 4) both and V unchanged

As we learnt in

Direction of Electric field -

Due to Positive Charge electric field is always away from the charge.

-

Direction of Electric field -

Due to Negative charge electric field is always towards the charge.

-

"Unit positive charge" will be repelled by  A and B and attracted by -q and -q downwards in the same direction. If they are exchanged the direction of the field will be opposite. In the case of potential, as it is a scalar, they cancel each other whatever may be their position.

Field is affected but not the potential.

Option 1)

changes,V remains unchanged

Correct

Option 2)

remains unchanged V changes

Incorrect

Option 3)

both and V change

Incorrect

Option 4)

both and V unchanged

Incorrect