Why does the cord of an electric heater not glow while the heating element does?

Why does the moon revolve round the earth?

What does an electric circuit mean?

Why does the conductivity of a solution decrease with dilution?

Why does a piece of red glass when heated and taken out glow with green light?

Why does mercury not cling to glass?

Why does the conductivity of solution decrease with dilution?

Why does the molality of a solution remain unchanged with temperature?

Heat is generated continuosly in an electric heater ,but its temperature becomes constant after some time.Why?