Current heating effect

Question 1

When there is an electric current flowing through a resistor, what is transferred?

Answer 1

energy is transferred, which heats the resistor

Question 2

When an electric current does work against electrical resistance, what happens?

Answer 2

electrical energy is dissipated as thermal energy in the surroundings

Question 3

How can unwanted thermal energy transfers be reduced?

Answer 3

By using low resistance wires. Wires that are better conductors, shorter or thicker will waster less energy as heat compared with longer, thinner wires of a poorer electrical conductor

Question 4

Advantages of the heating effect

Answer 4

Some appliances such as the iron, the heater and the fuse are designed to transfer energy to thermal energy by the heating effect of a current. This is useful for: heating water on a kettle, radiant heater, toasters, grills and ovens, underfloor heating

Question 5

Disadvantages of the heating effect?

Answer 5

If too much current flow in a circuit, then the heating effect can lead to the appliance catching fire or the user being burned. Too much current can flow if too many appliances are being used at the same time. Safety features such as correct fuses, circuit breakers and earthing need to be in place. In many devices, the heating effect of a current means that some energy is wasted.

Question 6

How is energy transferred to thermal energy in a resistor?

Answer 6

Collisions between moving electrons and the fixed metal ions in a lattice result in the kinetic energy of the electrons being transferred to thermal energy. The thermal energy is dissipated into the surroundings.