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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 628 · 40 questions
TalentJR

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.

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  1. 1.🧩 Which component makes things spin? (a) buzzer (b) transistor (c) diode (d) motor
  2. 2.💡 Does it save or waste electricity to leave fridge door open? (a) wastes electricity (b) saves electricity
  3. 3.🔺 A current of 1 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  4. 4.🌈 A resistor has the colour bands green, orange, orange. What is its value in kilo-ohms (kΩ)? =
  5. 5.🔺 A current of 0.2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  6. 6.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = V × I (c) R = V ÷ I (d) R = I ÷ V
  7. 7.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  8. 8.🔺 A current of 40 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  9. 9.True or false: to run fans in empty rooms wastes electricity. (a) False (b) True
  10. 10.🔺 A current of 20 mA flows when 4.4 V is joined across a resistor. What is its resistance (in ohms)?
  11. 11.🌈 In the resistor colour code, which number does grey stand for?
  12. 12.🔺 A 30 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  13. 13.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 volt (c) 1 watt (d) 1 kilowatt-hour (kWh)
  14. 14.💡 An LED is joined to a 9 V battery through a 470 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) lights up (b) does not light (c) may burn out
  15. 15.🔺 A current of 25 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  16. 16.True or false: a capacitor limits the current. (a) True (b) False
  17. 17.🔺 A 4 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  18. 18.⚡ Power tells us … (a) the length of a wire (b) the size of a cell (c) the colour of light (d) energy used each second
  19. 19.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) gets smaller (c) stays the same (d) gets bigger
  20. 20.🔺 A current of 20 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  21. 21.True or false: a transistor boosts a small signal. (a) False (b) True
  22. 22.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
  23. 23.📏 How many kilowatts (kW) is 850 W? =
  24. 24.🔺 A 12 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  25. 25.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  26. 26.True or false: to switch off empty rooms wastes electricity. (a) False (b) True
  27. 27.📏 In the water-pipe picture of a circuit, resistance is like … (a) the flow of water (b) a narrow pipe (c) the water pressure (d) a bigger tank
  28. 28.🧮 Four equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  29. 29.🔺 A current of 0.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  30. 30.🔺 A current of 10 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  31. 31.🔺 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
  32. 32.🔺 A current of 0.1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  34. 34.💡 An LED is joined to a 5 V battery through a 470 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) may burn out (c) lights up
  35. 35.🌈 A resistor has the colour bands brown, white, red. What is its value (in ohms)?
  36. 36.Which of these is measured in ohms (Ω)? (a) how much a part resists (b) current (c) the push of a cell (d) voltage
  37. 37.True or false: the voltmeter is joined in series. (a) False (b) True
  38. 38.What does a resistor do? (a) makes things spin (b) senses how bright it is (c) has coloured bands (d) lets current go one way
  39. 39.💡 An LED is joined to a 5 V battery through a 220 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
  40. 40.🌈 A resistor has the colour bands red, green, brown. What is its value (in ohms)?

Answer key

  1. motor
  2. wastes electricity
  3. 8
  4. 53
  5. 0.8
  6. R = V ÷ I
  7. anode (+)
  8. 100
  9. True
  10. 220
  11. 8
  12. 3
  13. 1 kilowatt-hour (kWh)
  14. lights up
  15. 5
  16. False
  17. 10
  18. energy used each second
  19. gets smaller
  20. 150
  21. True
  22. saves electricity
  23. 0.85
  24. 1
  25. 20
  26. False
  27. a narrow pipe
  28. 10
  29. 6
  30. 3
  31. I = V ÷ R
  32. 0.2
  33. cathode (−)
  34. lights up
  35. 1900
  36. how much a part resists
  37. False
  38. has coloured bands
  39. lights up
  40. 250

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