Electrical circuits questions

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In most homes use incandescent light bulbs. An incandescent light bulb has a coiled wire filament that, when the light is switched on, gets so hot that it glows. When a 100 W incandescent light bulb is connected to a 240 V supply the current from the supply is 0.42 A. Calculate the resistance of the filament of the bulb.
570 
If the light bulb is switched on for 30 minutes, 175 kJ of energy are wasted as heat. Calculate the power output of the heat that the bulb produces.
97 W
Many people are changing their incandescent bulbs to compact fluorescent lamps (CFLs) because a CFL wastes less energy as heat than an incandescent bulb. In the circuit shown, lamp A is the same 100 W incandescent bulb as in the circuit above, and lamp B is a 20 W CFL. Calculate the current through the 240 V supply.
0.50 A
The electric heater that Jack used has two elements, as shown in the circuit diagram. Element 1 has a power rating 1000 W, element 2 has a power rating 2000 W. If switch 1 is closed, calculate the current through element 1.
4.0 A
Calculate the total resistance of the circuit if both elements are switched on.
21 
Is this a series circuit or a parallel circuit. One word answer
• Series
Three identical 12 V bulbs are connected to a 32 V supply as shown in the diagram below. The ammeter measures a current of 1.5 A, calculate the total power used by the three bulbs.
48 W
Three identical 12 V bulbs are connected to a 32 V supply as shown in the diagram below. Assuming the resistance of each bulb stays at 7.1 Ω; calculate the maximum rated power of one bulb.
20 W
The circuit below shows a brake light, rated 21 W, connected to a 12 V battery. Calculate the resistance of the brake light bulb when it is glowing.
6.9 Ω