Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 262 · 40 questions

Remember (Find the topic, use the formula): Find the topic and the formula: V = I × R, I = V ÷ R, R = V ÷ I, P = V × I, units = W × h ÷ 1000. Change mA to A and kΩ to Ω before using a formula. Check: put your answer back into the formula.

1. 1.🌈 A resistor has the colour bands brown, orange, orange. What is its value in kilo-ohms (kΩ)? =
2. 2.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
3. 3.What does a diode do? (a) has coloured bands (b) lets current go one way (c) beeps for an alarm (d) glows using little power
4. 4.True or false: the voltmeter is joined across a part. (a) True (b) False
5. 5.🔺 A current of 50 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
6. 6.Which of these is measured in volts (V)? (a) current (b) resistance (c) voltage (d) the flow of charge
7. 7.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 5 % (c) 25 % (d) 0 %
8. 8.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
9. 9.🧾 A 50 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
10. 10.🔺 A 4 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
11. 11.🧮 Two equal 220 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
12. 12.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) less than either one (c) their sum (d) always zero
13. 13.🔺 A 7.5 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
14. 14.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 3 V supply. What current flows (in mA)?
15. 15.🌈 In the resistor colour code, which number does yellow stand for?
16. 16.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
17. 17.📏 In the water-pipe picture of a circuit, current is like … (a) the flow of water (b) the water pressure (c) a narrow pipe (d) the pipe colour
18. 18.⚡ Power tells us … (a) the size of a cell (b) the length of a wire (c) the colour of light (d) energy used each second
19. 19.🧩 A capacitor in a circuit can … (a) measure heat (b) make light (c) spin a wheel (d) store charge briefly
20. 20.📏 Which unit measures the flow of charge? (a) volt (V) (b) ampere (A) (c) ohm (Ω) (d) watt (W)
21. 21.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
22. 22.True or false: to unplug idle chargers saves electricity. (a) False (b) True
23. 23.Which of these wastes electricity? (a) close the fridge quickly (b) switch off empty rooms (c) use daylight to read (d) leave fridge door open
24. 24.🧩 Which component has coloured bands? (a) diode (b) thermistor (c) transistor (d) resistor
25. 25.💡 What does LED stand for? (a) low energy device (b) light energy dial (c) large electric dial (d) light-emitting diode
26. 26.Which of these is measured in amperes (A)? (a) power (b) voltage (c) energy used each second (d) current
27. 27.📏 How many ohms (Ω) is 2.2 kΩ?
28. 28.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) becomes zero (c) stays the same (d) gets bigger
29. 29.🔺 A current of 20 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
30. 30.🔍 Which is the odd one out? (a) unplug idle chargers (b) run fans in empty rooms (c) use LED lamps (d) use daylight to read
31. 31.📏 Which unit measures resistance? (a) ohm (Ω) (b) volt (V) (c) ampere (A) (d) watt (W)
32. 32.⚡ A 2.4 W device works on 24 V. What current does it take (in amperes)? =
33. 33.Which of these is measured in ohms (Ω)? (a) voltage (b) the push of a cell (c) energy used each second (d) resistance
34. 34.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
35. 35.🔺 A 0.5 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
36. 36.True or false: energy used each second is measured in watts (W). (a) False (b) True
37. 37.🧾 A 100 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
38. 38.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
39. 39.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V ÷ I (c) R = V + I (d) R = V × I
40. 40.⚡ A device works on 3 V and takes 0.1 A. What is its power (in watts)? =

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