Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 450 · 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.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
2. 2.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
3. 3.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V ÷ R (c) I = V × R (d) I = V + R
4. 4.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = I ÷ R (c) V = R ÷ I (d) V = I + R
5. 5.🌈 A resistor has the colour bands red, black, red. What is its value (in ohms)?
6. 6.True or false: energy used each second is measured in watts (W). (a) True (b) False
7. 7.🌈 A resistor has the colour bands orange, yellow, yellow. What is its value in kilo-ohms (kΩ)? =
8. 8.Which of these is measured in volts (V)? (a) resistance (b) current (c) power (d) the push of a cell
9. 9.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
10. 10.🔺 A current of 0.1 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
11. 11.📏 In the water-pipe picture of a circuit, voltage is like … (a) the pipe colour (b) the water tank lid (c) the tap handle (d) the water pressure
12. 12.🧩 Which component stores a little charge? (a) motor (b) transistor (c) potentiometer (d) capacitor
13. 13.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 4200 Ω resistor? (a) yellow-red-brown (b) yellow-red-red (c) yellow-red-orange (d) red-yellow-red
14. 14.🌈 In the resistor colour code, which number does yellow stand for?
15. 15.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to an 8 V supply. What current flows (in mA)?
16. 16.🌈 In the resistor colour code, which number does white stand for?
17. 17.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a capacitor (c) a resistor (d) a diode
18. 18.True or false: a transistor boosts a small signal. (a) False (b) True
19. 19.🔺 A current of 20 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
20. 20.True or false: on an LED, the longer leg is the anode (+). (a) False (b) True
21. 21.🔺 A current of 10 mA flows when 3.3 V is joined across a resistor. What is its resistance (in ohms)?
22. 22.🌈 In the resistor colour code, which number does red stand for?
23. 23.🔺 A current of 10 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
24. 24.True or false: a diode stores a little charge. (a) False (b) True
25. 25.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
26. 26.True or false: to run fans in empty rooms saves electricity. (a) False (b) True
27. 27.⚡ A 2.4 W device works on 24 V. What current does it take (in amperes)? =
28. 28.⚡ Power tells us … (a) the colour of light (b) the length of a wire (c) the size of a cell (d) energy used each second
29. 29.🧮 A 33 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
30. 30.🧮 Two equal 470 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
31. 31.🔺 A current of 0.25 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
32. 32.🔺 A 4 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
33. 33.🔺 A 3 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
34. 34.🌈 A resistor has the colour bands green, green, orange. What is its value (in ohms)?
35. 35.🧩 Which component blows if current is high? (a) LED (b) diode (c) fuse (d) capacitor
36. 36.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = I ÷ V (c) P = V × I (d) P = V + I
37. 37.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
38. 38.🔺 A current of 1.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
39. 39.🌈 A resistor has the colour bands brown, black, red. What is its value in kilo-ohms (kΩ)? =
40. 40.📏 How many ohms (Ω) is 1.3 kΩ?

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