Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 413 · 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 250 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
2. 2.⚡ Which formula gives electric power? (a) P = V × I (b) P = V + I (c) P = V ÷ I (d) P = I ÷ V
3. 3.🔺 A current of 20 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
4. 4.🔺 A 0.4 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
5. 5.🧩 Which component senses how hot it is? (a) resistor (b) fuse (c) buzzer (d) thermistor
6. 6.Which of these saves electricity? (a) iron one shirt at a time (b) run fans in empty rooms (c) switch off empty rooms (d) use old filament bulbs
7. 7.Which of these is measured in volts (V)? (a) voltage (b) the flow of charge (c) how much a part resists (d) resistance
8. 8.True or false: to unplug idle chargers saves electricity. (a) True (b) False
9. 9.⚡ An 18 W device works on 12 V. What current does it take (in amperes)? =
10. 10.🔺 A 10 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
11. 11.🌈 A resistor has the colour bands grey, brown, orange. What is its value in kilo-ohms (kΩ)? =
12. 12.⚡ A 0.75 W device works on 1.5 V. What current does it take (in amperes)? =
13. 13.🧩 Which component smooths a wobbly supply? (a) capacitor (b) motor (c) diode (d) thermistor
14. 14.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 50 % (c) 25 % (d) 0 %
15. 15.Which of these is measured in amperes (A)? (a) current (b) energy used each second (c) how much a part resists (d) power
16. 16.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
17. 17.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 890 Ω resistor? (a) white-grey-brown (b) grey-white-black (c) grey-white-brown (d) grey-white-red
18. 18.🧾 A family uses 60 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
19. 19.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a capacitor (c) a diode (d) a buzzer
20. 20.🔺 A current of 0.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
21. 21.🔺 A 60 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
22. 22.🧮 A 150 Ω resistor is joined in series with two equal 470 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
23. 23.⚡ A device works on 5 V and takes 1.5 A. What is its power (in watts)? =
24. 24.True or false: on an LED, the round-side leg is the anode (+). (a) False (b) True
25. 25.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
26. 26.🧮 Resistors of 47 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
27. 27.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
28. 28.⚡ A device works on 1.5 V and takes 1 A. What is its power (in watts)? =
29. 29.🌈 Which band is read first on a resistor? (a) any band (b) the widest gap (c) the one nearest an end (d) the gold band
30. 30.🌈 A resistor has the colour bands brown, grey, yellow. What is its value in kilo-ohms (kΩ)? =
31. 31.True or false: a resistor has coloured bands. (a) False (b) True
32. 32.🧾 A 1000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
33. 33.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
34. 34.🔺 A current of 20 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
35. 35.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
36. 36.True or false: the voltmeter measures current. (a) False (b) True
37. 37.🔺 A current of 2 A flows when 16 V is joined across a resistor. What is its resistance (in ohms)?
38. 38.True or false: the voltmeter is joined in series. (a) False (b) True
39. 39.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) becomes zero (c) stays the same (d) gets smaller
40. 40.True or false: a resistor limits the current. (a) False (b) True

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