Charging a material, such as polythene or copper, by rubbing involves the transfer of electric charges. The ability of a material to accumulate charge depends on two properties: electrical conductivity and the tendency to acquire or lose electrons.

1. Electrical Conductivity:

a) Polythene: Polythene is a poor conductor of electricity. When it is rubbed with a material like wool or a dry cloth, it acquires an electric charge and retains it for a relatively long time because the charges cannot move freely within the material.

b) Copper: Copper is an excellent conductor of electricity. When rubbed, the charges induced on its surface can move quickly throughout the material. As a result, the surface charge rapidly dissipates, making it harder to accumulate a significant charge on copper.

2. Tendency to Acquire or Lose Electrons:

a) Polythene: Polythene tends to lose electrons relatively easily and become positively charged when rubbed.

b) Copper: Copper exhibits a lesser tendency to lose or gain electrons, making it more challenging to charge by rubbing.

Combining these factors, it becomes easier to charge polythene by rubbing, while copper doesn't accumulate a significant charge because of its high electrical conductivity and weaker tendency to accept or donate electrons.