For a charged spherical ball, electrostatic potential inside the ball varies with r as V =2 a r^2+b. Here, a and b are constant and r is the distance…

For a charged spherical ball, electrostatic potential inside the ball varies with $\displaystyle r$ as $\displaystyle \mathrm{V}=2 a r^2+b$. Here, $\displaystyle a$ and $\displaystyle b$ are constant and r is the distance from the center. The volume charge density inside the ball is $\displaystyle -\lambda a \varepsilon$. The value of $\displaystyle \lambda$ is $\displaystyle \_\_\_\_$. $\displaystyle \varepsilon=$ permittivity of the medium