$A$ uniform electric field is prevailing in the $X$-direction in a certain region. The coordinates of points $P$,$Q$,and $R$ are $(0,0)$,$(2,0)$,and $(0,2)$ respectively. Which of the following alternatives is true for the potentials at these points?

$A$ point charge is placed at point $P$ as shown in the figure. $A$ hollow conducting sphere is placed in the electric field produced by it. If $V_A$,$V_B$,and $V_C$ are the potentials at points $A$,$B$,and $C$ respectively,then:

$A$ charge is moved from point $A$ to points $B, C, D,$ and $E$ in the electric field of a charge $Q$ placed at the center of a circle. The work done will be:

If a unit charge is taken from one point to another point over an equipotential surface,then

Which of the following statements is not true?

Two point charges $-Q$ and $+Q / \sqrt{3}$ are placed in the $xy$-plane at the origin $(0,0)$ and a point $(2,0)$,respectively,as shown in the figure. This results in an equipotential circle of radius $R$ and potential $V = 0$ in the $xy$-plane with its center at $(b, 0)$. All lengths are measured in meters.
$(1)$ The value of $R$ is. . . . meter.
$(2)$ The value of $b$ is. . . . . .meter.