Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 444 · 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 colour bands (1st digit, 2nd digit, multiplier) mark a 2800 Ω resistor? (a) red-grey-brown (b) grey-red-red (c) red-grey-orange (d) red-grey-red
2. 2.🧮 Resistors of 330 Ω, 33 Ω, 68 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
3. 3.🔺 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
4. 4.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
5. 5.True or false: on an LED, the leg by the flat edge is the anode (+). (a) True (b) False
6. 6.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 6100 Ω resistor? (a) blue-brown-red (b) blue-brown-brown (c) brown-blue-red (d) blue-brown-orange
7. 7.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
8. 8.🔺 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
9. 9.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water pressure (b) the tap handle (c) the water tank lid (d) the pipe colour
10. 10.🌈 A resistor has the colour bands blue, red, brown. What is its value (in ohms)?
11. 11.🧮 Four equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
12. 12.🔺 A current of 0.2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
13. 13.True or false: to leave the TV on standby wastes electricity. (a) False (b) True
14. 14.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 3.5 V supply. What current flows (in mA)?
15. 15.💡 A blue LED uses 3 V and should get 25 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
16. 16.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
17. 17.What does a buzzer do? (a) has coloured bands (b) is a resistance knob (c) beeps for an alarm (d) lets current go one way
18. 18.Which of these saves electricity? (a) leave the TV on standby (b) run fans in empty rooms (c) set the AC to 24 °C (d) leave fridge door open
19. 19.🔍 Which is the odd one out? (a) run fans in empty rooms (b) use old filament bulbs (c) iron one shirt at a time (d) use daylight to read
20. 20.🧮 A 3.25 V battery is joined to 5 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
21. 21.🌈 A resistor has the colour bands white, black, black. What is its value (in ohms)?
22. 22.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = R ÷ V (c) I = V + R (d) I = V × R
23. 23.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
24. 24.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a resistor (c) a motor (d) an LED
25. 25.💡 An LED is joined to a 9 V battery through a 330 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) may burn out (b) lights up (c) does not light
26. 26.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V ÷ I (c) R = V × I (d) R = V + I
27. 27.🔍 Which is the odd one out? (a) leave the TV on standby (b) iron one shirt at a time (c) leave fridge door open (d) unplug idle chargers
28. 28.What does a capacitor do? (a) smooths a wobbly supply (b) senses how bright it is (c) is a resistance knob (d) senses how hot it is
29. 29.Which of these is measured in volts (V)? (a) resistance (b) how much a part resists (c) power (d) the push of a cell
30. 30.🧮 Resistors of 33 Ω and 470 Ω are joined in series. What is the total resistance (in ohms)?
31. 31.🧮 Five equal 25 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
32. 32.True or false: a capacitor stores a little charge. (a) False (b) True
33. 33.💡 An LED is joined to a 3 V battery through a 330 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) may burn out (b) does not light (c) lights up
34. 34.🔺 A current of 0.2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
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 6 W device works on 24 V. What current does it take (in amperes)? =
37. 37.🧮 Two equal 220 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
38. 38.Which of these is measured in volts (V)? (a) the flow of charge (b) power (c) voltage (d) resistance
39. 39.💡 A red LED uses 2 V and should get 10 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
40. 40.🔺 A current of 20 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =

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