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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 658 · 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.

NameDateTime takenScore ___ / 40
  1. 1.True or false: to use daylight to read wastes electricity. (a) False (b) True
  2. 2.🧮 A 2.2 V battery is joined to 12 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
  3. 3.⚡ 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
  4. 4.True or false: an LED has coloured bands. (a) False (b) True
  5. 5.🔺 A current of 0.1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  6. 6.🧩 Which component glows using little power? (a) capacitor (b) buzzer (c) LED (d) diode
  7. 7.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
  8. 8.Which of these saves electricity? (a) switch off empty rooms (b) use old filament bulbs (c) iron one shirt at a time (d) leave fridge door open
  9. 9.🌈 A resistor has the colour bands yellow, brown, yellow. What is its value in kilo-ohms (kΩ)? =
  10. 10.🧮 Resistors of 330 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
  11. 11.What does a resistor do? (a) has coloured bands (b) is a resistance knob (c) beeps for an alarm (d) glows using little power
  12. 12.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
  13. 13.True or false: the flow of charge is measured in watts (W). (a) True (b) False
  14. 14.🔺 A current of 0.2 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.True or false: on an LED, the round-side leg is the anode (+). (a) False (b) True
  16. 16.🔺 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
  17. 17.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
  18. 18.💡 A blue LED uses 3 V and should get 25 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
  19. 19.🧩 A capacitor in a circuit can … (a) measure heat (b) spin a wheel (c) store charge briefly (d) make light
  20. 20.🔺 In the V-I-R triangle, how do we find R? (a) R = V ÷ I (b) R = V + I (c) R = I ÷ V (d) R = V × I
  21. 21.🔺 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
  22. 22.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
  23. 23.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V + I (d) P = V × I
  24. 24.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 25 % (c) 50 % (d) 5 %
  25. 25.🧮 Resistors of 33 Ω, 100 Ω, 20 Ω and 470 Ω are joined in series. What is the total resistance (in ohms)?
  26. 26.🔺 A current of 3 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  27. 27.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  28. 28.⚡ A device works on 9 V and takes 1.5 A. What is its power (in watts)? =
  29. 29.🌈 A resistor has the colour bands blue, red, orange. What is its value (in ohms)?
  30. 30.🧮 Resistors of 47 Ω, 10 Ω, 330 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
  31. 31.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  32. 32.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 1500 Ω resistor? (a) brown-green-brown (b) brown-green-orange (c) brown-green-red (d) green-brown-red
  33. 33.What does a diode do? (a) makes things spin (b) is a resistance knob (c) lets current go one way (d) turns a fan or wheels
  34. 34.💡 What happens if an LED is put in backwards? (a) it changes colour (b) it lights brighter (c) it does not light (d) it makes a sound
  35. 35.🧾 A 200 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
  36. 36.🔺 A current of 3 A flows when 45 V is joined across a resistor. What is its resistance (in ohms)?
  37. 37.🧮 Resistors of 470 Ω, 10 Ω and 470 Ω are joined in series. What is the total resistance (in ohms)?
  38. 38.🔺 A current of 0.5 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  39. 39.True or false: a fuse blows if current is high. (a) False (b) True
  40. 40.📏 In the water-pipe picture of a circuit, resistance is like … (a) a bigger tank (b) the water pressure (c) a narrow pipe (d) the flow of water

Answer key

  1. False
  2. 0.1
  3. energy used each second
  4. False
  5. 0.4
  6. LED
  7. 460
  8. switch off empty rooms
  9. 410
  10. 350
  11. has coloured bands
  12. saves electricity
  13. False
  14. 5
  15. True
  16. V = I × R
  17. 2300
  18. 80
  19. store charge briefly
  20. R = V ÷ I
  21. I = V ÷ R
  22. 204
  23. P = V × I
  24. 5 %
  25. 623
  26. 12
  27. anode (+)
  28. 13.5
  29. 62000
  30. 437
  31. 5
  32. brown-green-red
  33. lets current go one way
  34. it does not light
  35. 1.2
  36. 15
  37. 950
  38. 4
  39. True
  40. a narrow pipe

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