Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 469 · 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 part changes electrical energy into movement? (a) a fuse (b) a motor (c) an LED (d) a resistor
2. 2.🌈 In the resistor colour code, which number does orange stand for?
3. 3.🌈 A resistor has the colour bands yellow, yellow, orange. What is its value in kilo-ohms (kΩ)? =
4. 4.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
5. 5.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) True (b) False
6. 6.🌈 In the resistor colour code, which number does white stand for?
7. 7.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
8. 8.🌈 A resistor has the colour bands blue, red, red. What is its value (in ohms)?
9. 9.🔺 A current of 10 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
10. 10.🔺 A current of 2.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
11. 11.What does a diode do? (a) makes things spin (b) lets current go one way (c) turns a fan or wheels (d) senses how bright it is
12. 12.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
13. 13.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
14. 14.🌈 A resistor has the colour bands brown, brown, black. What is its value (in ohms)?
15. 15.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
16. 16.🧩 A capacitor in a circuit can … (a) make light (b) measure heat (c) store charge briefly (d) spin a wheel
17. 17.📏 How many kilowatts (kW) is 1600 W? =
18. 18.📏 In the water-pipe picture of a circuit, current is like … (a) the flow of water (b) the water pressure (c) the pipe colour (d) a narrow pipe
19. 19.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 670 Ω resistor? (a) blue-violet-brown (b) blue-violet-red (c) blue-violet-black (d) violet-blue-brown
20. 20.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
21. 21.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
22. 22.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
23. 23.🧮 Resistors of 68 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
24. 24.True or false: how much a part resists is measured in watts (W). (a) True (b) False
25. 25.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
26. 26.🔺 A current of 10 mA flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
27. 27.📏 How many milliamperes (mA) is 1.76 A?
28. 28.⚡ A device works on 24 V and takes 0.2 A. What is its power (in watts)? =
29. 29.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
30. 30.🧩 Which component boosts a small signal? (a) buzzer (b) resistor (c) LED (d) transistor
31. 31.⚡ Power tells us … (a) energy used each second (b) the size of a cell (c) the colour of light (d) the length of a wire
32. 32.🔺 A current of 1 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
33. 33.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 98 Ω resistor? (a) white-grey-brown (b) white-grey-black (c) grey-white-black (d) brown-grey-black
34. 34.🔺 A current of 1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
35. 35.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) stay the same (c) zero (d) bigger
36. 36.💡 What does LED stand for? (a) low energy device (b) large electric dial (c) light energy dial (d) light-emitting diode
37. 37.⚡ A device works on 3 V and takes 3 A. What is its power (in watts)? =
38. 38.🌈 In the resistor colour code, which number does black stand for?
39. 39.🧮 Resistors of 68 Ω, 22 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
40. 40.What does a resistor do? (a) limits the current (b) lets current go one way (c) senses how hot it is (d) blows if current is high

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