A small metal sphere on an insulating stand is charged to produce a radial electric field. At a distance of 12 cm from the centre of the sphere, the electric field strength is 4.5 × 104 N C-1.
What is the charge on the sphere?
5.7×10−9 C5.7 \times 10^{-9}\text{ C}5.7×10−9 C
7.2×10−8 C7.2 \times 10^{-8}\text{ C}7.2×10−8 C
6.0×10−7 C6.0 \times 10^{-7}\text{ C}6.0×10−7 C
7.2×10−4 C7.2 \times 10^{-4}\text{ C}7.2×10−4 C
