Physics
Conductors and Insulators
Practice questions
Why is it necessary to remove earthing first and the external charged object later in induction charging?What problem can occur if the external object is removed first while earthing remains connected in induction charging?Why can attraction occur in a polarised insulator even though its net charge does not change?Which is the most correct comparison between induction in a conductor and polarisation in an insulator?Why does charge produced by rubbing on an insulator not spread uniformly over the whole surface?If charge is localized on an insulator, how can the electric field around it be?What is the basic mistake in treating an insulator as equipotential like a conductor?Why is it difficult to retain static charge on a metal object held by hand?Which condition is most suitable for retaining static charge on a metal object for a long time?Why can the final charge become equal when two identical metal spheres are brought into contact?Why may charge not divide equally between two unequal conductors in contact?The electric field inside a conductor is zero. Does this prove that there is no charge on the conductor?If volume charge density inside a conductor is zero in electrostatic equilibrium, where is excess charge considered to be?Toward which state do free charges move while a conductor reaches electrostatic equilibrium?If the electric field inside a closed conductor is zero, what can be said about the energy associated with the electric field inside it?How does a closed metal cage protect its interior from an external electrostatic field?Why does a person inside a car receive relative protection during a lightning strike?Why is a lightning-protection rod made of metal and connected to Earth?What is the physical reason for keeping the tip of a lightning rod sharp?If an insulator has localized charge, why may touching one point to Earth not discharge the whole object immediately?