Potential Questions

Three concentric spherical shells have radii $a,b$ and $c$ ($a<b<c$) and have surface charge densities $\sigma ,-\sigma$ and $\sigma$ respectively. If $V_A,V_B$ and $V_C$ denote the potentials of the three shells, then for $c=a+b$, we have:

The potential difference that must be applied to stop the fastest photo electrons emitted by a nickel surface, having work function $5.01\text{ eV}$, when ultraviolet light of $200\text{ nm}$ falls on it, must be:

A particle of mass $M$ is at the centre of a spherical shell of mass $M$ and radius $a$. Gravitational potential at distance $a/2$ from centre is:

Electric potential $V=4x^2\text{V}$. The electric field at $(1,0,2)$ is:

Two metallic spheres of radii $1\text{cm}$ and $3\text{cm}$ are given charges of $-1\times 10^{-2}\text{C}$ and $5\times 10^{-2}\text{C}$, respectively. If these are connected by a conducting wire, the final charge on the bigger sphere is:

Four point charges $-Q,-q,2q$ and $2Q$ are placed, one at each corner of the square. The relation between $Q$ and $q$ for which the potential at the centre of the square is zero is:

$A,B$ and $C$ are three points in a uniform electric field $\vec{E}$ directed along the positive x-axis. $B$ is further left than $A$, and $A$ is further left than $C$. The electric potential is: