State Coulomb’s law.
The sphere and particle $P$ are both positively charged. State the direction of the force acting on particle $P$.
State the position of particle $P$ for the force to be maximum.
Determine the ratio $\dfrac{\text{force on particle }P\text{ at }x = r}{\text{force on particle }P\text{ at }x = 4r}$.
The sphere and the particle P are both charged positively. State the direction of the force acting on particle P.
State the position of particle P for the force to be maximum.
Determine the ratio $\dfrac{\text{force on particle P at } x = r}{\text{force on particle P at } x = 4r}$.
When the charge on the sphere is $6.0 \times 10^{-7}\,\text{C}$, the electric field strength at the surface of the sphere is $1.5 \times 10^{6}\,\text{V m}^{-1}$. Electrical breakdown (a spark) occurs when the electric field strength at the surface of the sphere exceeds $2.0 \times 10^{6}\,\text{V m}^{-1}$. Determine the additional charge that may be added to the sphere before breakdown occurs.