(N/A) The process of charging a conductor without physical contact is called charging by induction.
$1$. Take an uncharged metallic sphere mounted on an insulating stand,as shown in Fig. $(a)$.
$2$. Bring a negatively charged rod close to the metallic sphere,as shown in Fig. $(b)$. The free electrons in the sphere are repelled by the rod and move to the farther end,leaving the near end positively charged.
$3$. Connect the sphere to the ground using a conducting wire. The free electrons at the farther end flow to the ground due to repulsion,while the positive charges at the near end remain held due to the attractive force of the rod,as shown in Fig. $(c)$.
$4$. Disconnect the sphere from the ground. The positive charge remains trapped at the near end,as shown in Fig. $(d)$.
$5$. Finally,remove the charged rod. The positive charge redistributes itself uniformly over the surface of the sphere,as shown in Fig. $(e)$.
In this experiment,the sphere is charged by induction,and the rod does not lose any of its charge. $A$ similar process can be used to charge a sphere negatively by using a positively charged rod.