1.What is the current flowing in a circuit if 30C are passed in 1 minute? Q = It 30 = I x 60 I = 30/60 0.5A answer
2.What voltage would be measured over a 100 Ω resistor when 10mA flows through it? V = IR V = 0.01 x 100 1V answer
3.How many joules of energy are transferred by a 60W bulb every second? P = E/t 60 = E/1 E =60/1 60J answer
4. Calculate the size of the current flowing in a 3kW mains operated appliance. answer 13A
5.A television draws 0.1 A and has a resistance of 5000Ω. Calculate the power consumption P = IV P = 0.1 x W answer
6.How many 1.5V bulbs operating at their correct voltage could be connected in series with a 6V cell? Vs = V1+ V2… 6 = = 4(1.5) Four bulbs answer
7. What is the total resistance of a set of Christmas lights comprising of 30 individual 10Ω lamps in series? Rt = R1+R2+… Rt= 30(10) 3600 Ω or 3.6kΩ answer
8. An electrical supply for a caravan delivers a total current of 2A to the fridge and lighting circuits. If the lights use 0.25A, what is the operating current of the fridge? It = I lights +I fridge 2= I fridge I fridge = A answer
9.What is the total resistance of three 90Ω resistors connected in parallel? 1/Rt = 1/R1+1/R2+1/R3 1/Rt = 1/90+1/90+1/90 1/Rt = 3/90 Rt = 90/3 30 Ω answer
10.Work out the enegy used in kWhr for a 2000 W electric heater which is used for 45 mins? E = Pt E= 2(kW)x 0.75(hr) 1.5kWhr answer
11.How many joules are used if a tumble dryer uses 0.75 kWh? 750Whr 750J/s(hr) 750x kJ or J answer
12. Select the appropriate formula from your data book.. That shows the relationship between charge, current and time. Q=It answer
13. Select the appropriate formula from your data book.. That shows the relationship between voltage, current and resistance. V = IR answer
14. State Ohm’s Law. V = IR answer
15. Rt = R1+R2+R3 answer Select the appropriate formula from your data book.. To calculate resistances in series.
16. 1/Rt= 1/R1 +1/R2 + 1/R3 answer Select the appropriate formula from your data book.. For combining resistors in parallel.
17. State the relationship between Energy and Power P = E/t answer