Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 427 · 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.🌈 In the resistor colour code, which number does green stand for?
2. 2.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
3. 3.🌈 A resistor has the colour bands green, red, orange. What is its value (in ohms)?
4. 4.True or false: to leave fridge door open wastes electricity. (a) True (b) False
5. 5.🔺 A 1 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
6. 6.🔺 A 2.4 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
7. 7.🌈 A resistor has the colour bands grey, orange, black. What is its value (in ohms)?
8. 8.🔺 A current of 40 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
9. 9.🔍 Which is the odd one out? (a) close the fridge quickly (b) leave the TV on standby (c) use LED lamps (d) set the AC to 24 °C
10. 10.🌈 A resistor has the colour bands brown, black, orange. What is its value (in ohms)?
11. 11.📏 Which unit measures resistance? (a) ohm (Ω) (b) volt (V) (c) ampere (A) (d) watt (W)
12. 12.🔺 A current of 50 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
13. 13.📏 How many amperes (A) is 1300 mA? =
14. 14.🧾 A 100 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
15. 15.🔺 A current of 0.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
16. 16.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a resistor (c) a motor (d) an LED
17. 17.🌈 Which band is read first on a resistor? (a) the widest gap (b) the one nearest an end (c) the gold band (d) any band
18. 18.🧾 A family uses 20 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
19. 19.🔺 A current of 10 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
20. 20.📏 Which unit measures power? (a) volt (V) (b) ampere (A) (c) watt (W) (d) ohm (Ω)
21. 21.🌈 In the resistor colour code, which number does grey stand for?
22. 22.🧾 Which lamp gives the same light for the least power? (a) an LED lamp (b) a filament bulb (c) an oil lamp (d) a candle
23. 23.🧮 Four equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
24. 24.🔺 An 18 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
25. 25.True or false: current is measured in amperes (A). (a) True (b) False
26. 26.⚡ A 4.8 W device works on 24 V. What current does it take (in amperes)? =
27. 27.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it changes colour (c) it makes a sound (d) it does not light
28. 28.🌈 In the resistor colour code, which number does violet stand for?
29. 29.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
30. 30.🔺 A current of 25 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
31. 31.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) zero (c) bigger (d) stay the same
32. 32.🔺 A current of 0.25 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
33. 33.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) stays the same (c) becomes zero (d) gets bigger
34. 34.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a capacitor (c) a diode (d) a buzzer
35. 35.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
36. 36.🔺 A current of 25 mA flows when 6.25 V is joined across a resistor. What is its resistance (in ohms)?
37. 37.Which of these is measured in volts (V)? (a) energy used each second (b) resistance (c) the flow of charge (d) the push of a cell
38. 38.📏 How many amperes (A) is 2160 mA? =
39. 39.True or false: a motor glows using little power. (a) True (b) False
40. 40.💡 What does LED stand for? (a) low energy device (b) large electric dial (c) light energy dial (d) light-emitting diode

Free electronics lessons, practice and worksheets at talentjr.in/electronics-for-kids