Appeared in: 2026 (3 sets)
Assume that the surface charge density of the Earth is $1$ electron charge/$\text{m}^2$. The potential of the Earth's surface (radius $6400\text{ km}$) will be :
(A) $- 0\cdot 12\text{ V}$
(B) $- 0\cdot 21\text{ V}$
(C) $+ 2\cdot 1\text{ V}$
(D) $+ 1\cdot 2\text{ V}$