class 10 electricity

When a current 'I' flows through a resistance 'R' for time 't' the electrical energy spent is given by

Two electric bulbs have resistances in the ratio 1:2. If they are joined in series, the energy consumed in them is in the ratio.

At a given time, a house is supplied with 100 A at 220 V. How many 75 W, 220 V light bulbs could be switched on in the house at the same time (if they are all connected in parallel)?

If the current flowing through a fixed resistor is halved, the heat produced in it will become: