_A point charge q is placed in a cavity in a metal block. If a charge Q is brought outside the metal, will the charge q feel an electric force? Explain how the external charge Q affects charge distribution of the metal block.

It will not feel any electrostatic force becuase inside the metal block is cavity. so will not be any electric field hence it will not experince any electrostatic force since charge distributed on the surface hence total charge will be on the surface is q+Q.