Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 629 · 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.💡 What does LED stand for? (a) light energy dial (b) light-emitting diode (c) large electric dial (d) low energy device
2. 2.⚡ A 72 W device works on 24 V. What current does it take (in amperes)? =
3. 3.🔺 A current of 20 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
4. 4.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 100 (b) 10 (c) 1024 (d) 1000
5. 5.🔺 A 1 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
6. 6.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
7. 7.🧮 Resistors of 150 Ω and 22 Ω are joined in series. What is the total resistance (in ohms)?
8. 8.🌈 A resistor has the colour bands yellow, green, red. What is its value in kilo-ohms (kΩ)? =
9. 9.🌈 A resistor has the colour bands grey, orange, orange. What is its value in kilo-ohms (kΩ)? =
10. 10.🧮 A 330 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
11. 11.📏 How many ohms (Ω) is 2.8 kΩ?
12. 12.🔺 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
13. 13.🌈 A resistor has the colour bands red, green, orange. What is its value (in ohms)?
14. 14.🔺 A current of 2.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
15. 15.🧮 Five equal 25 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
16. 16.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
17. 17.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = V ÷ I (c) R = I ÷ V (d) R = V × I
18. 18.🔺 A 22.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
19. 19.🌈 In the resistor colour code, which number does yellow stand for?
20. 20.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 50 % (c) 25 % (d) 5 %
21. 21.True or false: how much a part resists is measured in amperes (A). (a) True (b) False
22. 22.🔺 A current of 0.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
23. 23.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
24. 24.⚡ Which formula gives electric power? (a) P = V + I (b) P = V ÷ I (c) P = V × I (d) P = I ÷ V
25. 25.🔺 A current of 10 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
26. 26.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
27. 27.🔺 A current of 0.2 A flows when 0.6 V is joined across a resistor. What is its resistance (in ohms)?
28. 28.🌈 A resistor has the colour bands grey, brown, orange. What is its value (in ohms)?
29. 29.🔺 A 1 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
30. 30.What does a motor do? (a) makes things spin (b) limits the current (c) glows using little power (d) stores a little charge
31. 31.⚡ A 4.5 W device works on 1.5 V. What current does it take (in amperes)? =
32. 32.📏 In the water-pipe picture of a circuit, voltage is like … (a) the tap handle (b) the pipe colour (c) the water tank lid (d) the water pressure
33. 33.🧮 Resistors of 20 Ω, 50 Ω, 330 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
34. 34.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) zero (c) bigger (d) stay the same
35. 35.What does a motor do? (a) glows using little power (b) lets current go one way (c) turns a fan or wheels (d) smooths a wobbly supply
36. 36.🌈 A resistor has the colour bands violet, blue, red. What is its value (in ohms)?
37. 37.🔺 A 7.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
38. 38.True or false: the voltmeter is joined across a part. (a) True (b) False
39. 39.🔺 A current of 0.25 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
40. 40.🧮 Resistors of 330 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?

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