(a)[2]
State Coulomb’s law for point charges.
(b(i))[2]
Use Fig. 6.2 to explain whether the two spheres have charges of the same sign or of opposite sign.
(b(ii))[3]
A proton is at point $P$ where $x = 5.0\,\text{cm}$. Use information from Fig. 6.2 to determine the proton’s acceleration.
(c)[2]
Use data from Fig. 6.2 to state the value of $x$ at which the rate of change of electric potential is greatest. Give the reason for the value you choose.