Question

2. Do you expect the resistance of a light bulb to remain constant as the current through it is increased and the filament goes from red-hot to white-hot? Explain why or why not.

Answer 1

Remember that as the temperature of an object increases, the kinetic energy of the particles inside it also increases.

So, if the temperature of a wire increases, the kinetic energy of the particles inside increases. Then when the electrons try to flow through the wire, the probability of a collision is increased (then the resistance increases). Thus, if the filament goes from red-hot to white-hot (so the temperature of the wire increases) we can conclude that the resistance that the current experiences also increases.

So no, we can not expect the resistance of the light bulb to remain constant as the filament goes from red-hot to white-hot.