A point charge Q is placed at point O as shown in the figure. The pote

1.	A point charge Q is placed at point O as shown in the figure. The potential difference VA – VB is positive. Is the charge Q negative or positive?
Answer» We know that, V = \(\cfrac{1}{4\pi\varepsilon_0}\cfrac{Q}r\) ⇒ V \(\propto\cfrac1r\) The potential due to a point charge decreases with increase of distance. V_A – V_B > 0 ⇒ V_A > V_B Hence, the charge Q is positive.

A point charge Q is placed at point O as shown in the figure. The potential difference VA – VB is positive. Is the charge Q negative or positive?

Answer»

We know that, V = \(\cfrac{1}{4\pi\varepsilon_0}\cfrac{Q}r\)

⇒ V \(\propto\cfrac1r\)

The potential due to a point charge decreases with increase of distance.

V_A – V_B > 0 ⇒ V_A > V_B

Hence, the charge Q is positive.