Question

An electrical heater has a resistance of 5 ohms and operates on a 120v power source;calculate the thermal energy in joules supplied by the heater in 12 seconds

Answer 1

Given: Resistance of an electric heater(R)= 5 ohms

          The Voltage of the power source(V)= 120V

           Time(T)= 12 seconds

To find The thermal energy in joules supplied by the heater in 12 seconds.

Solution: The energy of the motion of the molecules inside a system or a substance or an object is said to be thermal energy. The movement of heat is an application of thermal energy.

Now from above, R= 5 ohms, V=120V, T= 12 seconds

We know that Thermal energy(E)=(V²×T)÷R

                                                      =((120)²×12)÷5joules

                                                      =(14400×12)÷5joules

                                                      =172800÷5joules

                                                      =34560joules

Hence, the thermal energy in joules supplied by the heater in 12 seconds is 34560joules.