A spherical conductor has a radius of 14.0 $\mathrm{cm}$ and a charge of 26.0$\mu \mathrm{C}$ . Calculate the electric field and the electric potential at $(\mathrm{a}) r=10.0 \mathrm{cm},(\mathrm{b}) r=20.0 \mathrm{cm},$ and $(\mathrm{c}) r=$ 14.0 $\mathrm{cm}$ from the center.