The UK mains voltage is 230 V and alternating current means the current repeatedly reverses direction, so this Year 10 sheet opens with the two facts of home supply. The key records the live wire as the dangerous one and hertz as the frequency unit.
Key Takeaways
The mains voltage in the UK is 230 V (Q1).
In a.c. the current repeatedly reverses direction (Q2).
Q3 records the live wire as dangerous.
Section A: Multiple Choice Questions (1 Mark Each)
Choose the correct option for each question.
1.The mains voltage in the UK is
(a) 230 V(b) 110 V(c) 12 V(d) 1000 V
2.Mains electricity uses alternating current (a.c.), which means
(a) the current repeatedly reverses direction(b) the current flows one way only(c) the voltage is always zero(d) the current is constant
3.Which wire carries the current and is coloured brown?
(a) the live wire(b) the neutral wire(c) the earth wire(d) the fuse wire
4.The earth wire protects users against
(a) a fault that makes the metal casing live(b) too much light(c) power cuts(d) high electricity bills
5.A fuse is rated by its
(a) current(b) voltage(c) colour(d) length
6.The number of complete cycles of the mains supply in one second is called the
(a) frequency, measured in hertz(b) voltage, measured in volts(c) power, measured in watts(d) resistance, measured in ohms
Section B: Short Answer Type Questions (2 Marks Each)
Show all steps clearly.
7.State the value of the UK mains voltage and frequency.
8.What is the difference between a.c. and d.c.?
9.Name the three wires in a mains cable and state their colours.
10.What is the function of the earth wire?
11.Why is a fuse placed in the live wire?
12.Why are metal-cased appliances earthed?
13.What does the power rating of an appliance tell you?
14.Give one reason why power is transmitted at high voltage in the national grid.
Section C: Numericals & Word Problems (3 Marks Each)
Apply the concepts to solve the problems. Show all working.
15.A kettle draws a current of 8 A. Using the rule that a fuse should be rated above the appliance current, state whether a 13 A fuse is suitable.
16.A 230 V heater has a power of 2300 W. Using I = P ÷ V, find the current and state whether a 13 A fuse is suitable.
17.A 60 W lamp works on 230 V. Using I = P ÷ V, find the current. Then choose a suitable fuse from 1 A, 3 A and 5 A.
18.An appliance uses 2 kW for 3 hours. Using energy = power × time, find the energy used in kWh.
19.The frequency of the mains supply is 50 Hz. Using T = 1 ÷ f, find the period.
20.A 2000 W appliance runs for 5 hours. Using energy = power × time, find the energy used in kWh.
Answer Key
1. a) 230 V
2. a) the current repeatedly reverses direction
3. a) the live wire
4. a) a fault that makes the metal casing live
5. a) current
6. a) frequency, measured in hertz
7. Refer to solution guide.
8. Refer to solution guide.
9. Refer to solution guide.
10. Refer to solution guide.
11. Refer to solution guide.
12. Refer to solution guide.
13. Refer to solution guide.
14. Refer to solution guide.
15. Refer to solution guide.
16. Refer to solution guide.
17. Refer to solution guide.
18. Refer to solution guide.
19. Refer to solution guide.
20. Refer to solution guide.
End of Worksheet
People Also Ask
What is the mains voltage in the UK?
230 V, option (a) in this worksheet (Q1).
What does alternating current mean?
The current repeatedly reverses direction, option (a) in this worksheet (Q2).
Which wire carries the dangerous voltage?
The live wire, option (a) in this worksheet (Q3).
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