The potential at point $A$ is $3 \ V$ and at point $B$ is $7 \ V$. An electron is moving towards $A$ from $B$. Which of the following statements is correct?

Two particles $A$ and $B$ having the same mass have charges $+q$ and $+4q$ respectively. When they are allowed to fall from rest through the same electric potential difference,the ratio of their speeds $v_A$ to $v_B$ will be:

The electric potential of the Earth is taken to be zero because the Earth is a good:

$1 \ eV = ...... \ J$. (Fill in the gap)

$A$ charge of $5\,C$ is given a displacement of $0.5\,m$. The work done in the process is $10\,J$. The potential difference between the two points will be.......$V$

Given below are two statements $:$ one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A :$ Work done in moving a test charge between two points inside a uniformly charged spherical shell is zero,no matter which path is chosen.
Reason $R :$ Electrostatic potential inside a uniformly charged spherical shell is constant and is same as that on the surface of the shell.
In the light of the above statements,choose the correct answer from the options given below.