Let 's find out the heat developed in 3 minute by a device of resistance `920 Omega` working under 230 V.

Let 's calculate the heat developed when 3A current flows through an electric iron box designed to work under '230 V'.

If the resistance of two soldering irons working in 250 V are 500 Omega and 750 Omega . Calculate the heat produced in 5 minutes in the soldering iron having resistance 750 Omega .

According to Joule 's Law the heat generated due to flow of current is H = I^2 Rt . Will the heat developed increase on increasing the resistance without changing the voltage ? Explain.