Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 912 · 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.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 4300 Ω resistor? (a) yellow-orange-orange (b) yellow-orange-red (c) orange-yellow-red (d) yellow-orange-brown
2. 2.🔺 A 10 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
3. 3.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
4. 4.🧩 A capacitor in a circuit can … (a) spin a wheel (b) make light (c) measure heat (d) store charge briefly
5. 5.🧮 Four equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
6. 6.🧾 A family uses 160 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
7. 7.True or false: energy used each second is measured in watts (W). (a) True (b) False
8. 8.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
9. 9.💡 What happens if an LED is put in backwards? (a) it changes colour (b) it makes a sound (c) it does not light (d) it lights brighter
10. 10.Which of these is measured in watts (W)? (a) energy used each second (b) how much a part resists (c) voltage (d) resistance
11. 11.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V × I (d) P = V + I
12. 12.Which of these saves electricity? (a) use old filament bulbs (b) switch off empty rooms (c) iron one shirt at a time (d) leave fridge door open
13. 13.🌈 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
14. 14.🔺 A current of 1.5 A flows when 4.5 V is joined across a resistor. What is its resistance (in ohms)?
15. 15.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = I ÷ V (c) R = V × I (d) R = V ÷ I
16. 16.True or false: to close the fridge quickly wastes electricity. (a) True (b) False
17. 17.📏 How many kilo-ohms (kΩ) is 2700 Ω? =
18. 18.True or false: a capacitor smooths a wobbly supply. (a) False (b) True
19. 19.⚡ A device works on 12 V and takes 0.1 A. What is its power (in watts)? =
20. 20.🔍 Which is the odd one out? (a) leave fridge door open (b) run fans in empty rooms (c) switch off empty rooms (d) leave the TV on standby
21. 21.Which of these saves electricity? (a) leave fridge door open (b) use old filament bulbs (c) leave the TV on standby (d) use LED lamps
22. 22.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
23. 23.🧮 Two equal 220 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
24. 24.🌈 A resistor has the colour bands blue, white, red. What is its value (in ohms)?
25. 25.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
26. 26.🔺 A current of 40 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
27. 27.🔺 A current of 10 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
28. 28.Which of these is measured in amperes (A)? (a) power (b) the push of a cell (c) the flow of charge (d) resistance
29. 29.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
30. 30.🔺 A current of 50 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
31. 31.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 50 % (c) 25 % (d) 0 %
32. 32.🧾 A 2000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
33. 33.💡 What does LED stand for? (a) large electric dial (b) low energy device (c) light energy dial (d) light-emitting diode
34. 34.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = R ÷ I (c) V = I × R (d) V = I + R
35. 35.True or false: resistance is measured in volts (V). (a) True (b) False
36. 36.🧮 Resistors of 20 Ω, 470 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
37. 37.🌈 In the resistor colour code, which number does white stand for?
38. 38.🔺 An 18 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
39. 39.🧮 A 6 V battery is joined to 4 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
40. 40.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?

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