Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 711 · 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 unit measures the flow of charge? (a) ampere (A) (b) watt (W) (c) volt (V) (d) ohm (Ω)
2. 2.🔺 A current of 2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
3. 3.🔺 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
4. 4.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
5. 5.🧮 A 330 Ω resistor is joined in series with two equal 330 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
6. 6.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = V + R (c) I = V × R (d) I = R ÷ V
7. 7.🔺 A current of 2 A flows when 16 V is joined across a resistor. What is its resistance (in ohms)?
8. 8.🔺 A 6 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
9. 9.🔺 A current of 3 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
10. 10.🔺 A current of 50 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
11. 11.What does a transistor do? (a) boosts a small signal (b) smooths a wobbly supply (c) has coloured bands (d) glows using little power
12. 12.🧮 Resistors of 22 Ω, 330 Ω, 100 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
13. 13.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 9800 Ω resistor? (a) white-grey-brown (b) white-grey-orange (c) white-grey-red (d) grey-white-red
14. 14.📏 How many watts (W) is 4.9 kW?
15. 15.📏 Which unit measures voltage? (a) ampere (A) (b) volt (V) (c) ohm (Ω) (d) watt (W)
16. 16.🌈 In the resistor colour code, which number does brown stand for?
17. 17.🔺 A current of 0.2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
18. 18.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
19. 19.⚡ A device works on 9 V and takes 1.5 A. What is its power (in watts)? =
20. 20.🧮 Four equal 80 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
21. 21.True or false: a buzzer turns a fan or wheels. (a) False (b) True
22. 22.🧮 Two resistors in parallel give a total that is … (a) their sum (b) less than either one (c) always zero (d) more than either one
23. 23.📏 Which unit measures energy used each second? (a) ohm (Ω) (b) ampere (A) (c) watt (W) (d) volt (V)
24. 24.⚡ A 1.5 W device works on 1.5 V. What current does it take (in amperes)? =
25. 25.🔺 A current of 0.1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
26. 26.🌈 A resistor has the colour bands green, red, yellow. What is its value in kilo-ohms (kΩ)? =
27. 27.What does an LDR do? (a) stores a little charge (b) glows using little power (c) senses how bright it is (d) makes a beeping sound
28. 28.What does a diode do? (a) lets current go one way (b) boosts a small signal (c) turns a fan or wheels (d) blows if current is high
29. 29.Which of these is measured in volts (V)? (a) power (b) how much a part resists (c) resistance (d) the push of a cell
30. 30.🔺 A current of 3 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
31. 31.🧮 A 1.6 V battery is joined to 12 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
32. 32.What does an LED do? (a) stores a little charge (b) boosts a small signal (c) makes a beeping sound (d) glows using little power
33. 33.🧩 A capacitor in a circuit can … (a) make light (b) measure heat (c) spin a wheel (d) store charge briefly
34. 34.⚡ Which formula gives electric power? (a) P = V + I (b) P = V ÷ I (c) P = I ÷ V (d) P = V × I
35. 35.⚡ Power tells us … (a) energy used each second (b) the size of a cell (c) the length of a wire (d) the colour of light
36. 36.💡 Why does an LED need a resistor in series? (a) to make it brighter (b) to store charge (c) to change its colour (d) to limit the current
37. 37.📏 How many milliamperes (mA) is 2.4 A?
38. 38.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
39. 39.🧮 A 10 Ω resistor is joined in series with two equal 50 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
40. 40.🧮 A 150 Ω resistor is joined in series with two equal 100 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?

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