Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 401 · 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.🧮 A 220 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)?
2. 2.🌈 A resistor has the colour bands orange, brown, orange. What is its value (in ohms)?
3. 3.⚡ Which formula gives electric power? (a) P = V × I (b) P = V ÷ I (c) P = V + I (d) P = I ÷ V
4. 4.📏 Which unit measures energy used each second? (a) volt (V) (b) watt (W) (c) ohm (Ω) (d) ampere (A)
5. 5.🔺 A current of 10 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
6. 6.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
7. 7.🔺 A 7.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
8. 8.⚡ 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
9. 9.🔺 A current of 25 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
10. 10.🧮 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
11. 11.🔺 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
12. 12.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
13. 13.True or false: the ammeter is joined in series. (a) False (b) True
14. 14.🔺 A 1.6 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
15. 15.📏 How many amperes (A) is 470 mA? =
16. 16.🧮 Resistors of 50 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
17. 17.🌈 A resistor has the colour bands yellow, blue, red. What is its value in kilo-ohms (kΩ)? =
18. 18.🧩 Which component smooths a wobbly supply? (a) capacitor (b) potentiometer (c) resistor (d) fuse
19. 19.🧮 Two equal 220 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
20. 20.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
21. 21.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
22. 22.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
23. 23.Which of these is measured in watts (W)? (a) voltage (b) how much a part resists (c) energy used each second (d) resistance
24. 24.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) stays the same (c) gets smaller (d) gets bigger
25. 25.True or false: a transistor boosts a small signal. (a) True (b) False
26. 26.🔺 A current of 0.25 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
27. 27.🌈 A resistor has the colour bands yellow, violet, red. What is its value in kilo-ohms (kΩ)? =
28. 28.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
29. 29.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
30. 30.🧮 An 11 V battery is joined to 12 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
31. 31.🔺 A 1 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
32. 32.🧩 A capacitor in a circuit can … (a) spin a wheel (b) store charge briefly (c) make light (d) measure heat
33. 33.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 10 hours. How many watt-hours (Wh) are saved?
34. 34.🧩 Which part changes electrical energy into movement? (a) a resistor (b) an LED (c) a fuse (d) a motor
35. 35.📏 Which unit measures the push of a cell? (a) ohm (Ω) (b) ampere (A) (c) watt (W) (d) volt (V)
36. 36.True or false: on an LED, the longer leg is the anode (+). (a) False (b) True
37. 37.Which of these wastes electricity? (a) run fans in empty rooms (b) close the fridge quickly (c) switch off empty rooms (d) unplug idle chargers
38. 38.🧮 Resistors of 50 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?
39. 39.True or false: energy used each second is measured in amperes (A). (a) False (b) True
40. 40.🌈 A resistor has the colour bands red, violet, yellow. What is its value in kilo-ohms (kΩ)? =

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