Question

Before World War II, some radios got power through a "resistance cord" that had a significant resistance. Such a resistance cord reduces the voltage to a desired level for the radio’s tubes and the like, and it saves the expense of a transformer. Explain why resistance cords become warm and waste energy when the radio is on.

a) Resistance cords act as heaters.

b) Energy is lost as heat due to the current flowing through the resistance.

c) Resistance cords improve efficiency.

d) Resistance cords cool down when the radio is on.

Answer 1

Resistance cords become warm and waste energy when the radio is on because energy is lost as heat due to the current flowing through the resistance.

Step-by-step explanation:

Resistance cords become warm and waste energy when the radio is on because energy is lost as heat due to the current flowing through the resistance. When current passes through the resistance cord, the collisions between the electrons and the particles of the conductor transfer kinetic energy, causing the electrons to lose kinetic energy and slow down. This energy is converted into heat, which is why the resistance cord becomes warm.