MCQ
A solid metallic sphere has a charge $ + \,3Q$. Concentric with this sphere is a conducting spherical shell having charge $ - Q$. The radius of the sphere is $a$ and that of the spherical shell is $b(b > a)$. What is the electric field at a distance $R(a < R < b)$ from the centre
- A$\frac{Q}{{2\pi {\varepsilon _0}R}}$
- B$\frac{{3Q}}{{2\pi {\varepsilon _0}R}}$
- ✓$\frac{{3Q}}{{4\pi {\varepsilon _0}{R^2}}}$
- D$\frac{{4Q}}{{4\pi {\varepsilon _0}{R^2}}}$
