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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 623 · 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.🌈 A resistor has the colour bands orange, blue, orange. What is its value (in ohms)?
  2. 2.⚡ A 1.2 W device works on 12 V. What current does it take (in amperes)? =
  3. 3.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
  4. 4.📏 How many kilowatts (kW) is 200 W? =
  5. 5.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  6. 6.⚡ Power tells us … (a) the colour of light (b) the size of a cell (c) energy used each second (d) the length of a wire
  7. 7.🔺 A current of 0.25 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.True or false: to leave the TV on standby saves electricity. (a) True (b) False
  9. 9.True or false: to use LED lamps saves electricity. (a) False (b) True
  10. 10.⚡ A 6 W device works on 12 V. What current does it take (in amperes)? =
  11. 11.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = V + R (c) I = R ÷ V (d) I = V ÷ R
  12. 12.⚡ A 27 W device works on 9 V. What current does it take (in amperes)? =
  13. 13.🌈 A resistor has the colour bands violet, grey, yellow. What is its value in kilo-ohms (kΩ)? =
  14. 14.🔺 An 18.8 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  15. 15.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a filament bulb (c) a candle (d) an LED lamp
  16. 16.📏 How many milliamperes (mA) make 1 ampere? (a) 1000 (b) 100 (c) 10 (d) 60
  17. 17.Which of these is measured in ohms (Ω)? (a) power (b) energy used each second (c) how much a part resists (d) voltage
  18. 18.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  19. 19.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
  20. 20.🧩 Which component senses how bright it is? (a) resistor (b) diode (c) LDR (d) capacitor
  21. 21.⚡ A device works on 12 V and takes 1 A. What is its power (in watts)? =
  22. 22.⚡ A device works on 24 V and takes 0.25 A. What is its power (in watts)? =
  23. 23.🔺 A current of 1.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  24. 24.🔺 A current of 0.2 A flows when 0.4 V is joined across a resistor. What is its resistance (in ohms)?
  25. 25.Which of these saves electricity? (a) use old filament bulbs (b) iron one shirt at a time (c) close the fridge quickly (d) run fans in empty rooms
  26. 26.📏 Which unit measures resistance? (a) watt (W) (b) ohm (Ω) (c) volt (V) (d) ampere (A)
  27. 27.True or false: to use daylight to read saves electricity. (a) True (b) False
  28. 28.🧮 Two resistors in parallel give a total that is … (a) their sum (b) always zero (c) more than either one (d) less than either one
  29. 29.True or false: the voltmeter measures voltage. (a) False (b) True
  30. 30.Which of these is measured in amperes (A)? (a) voltage (b) current (c) resistance (d) how much a part resists
  31. 31.🧮 A 5.5 V battery is joined to 10 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  32. 32.True or false: on an LED, the shorter leg is the cathode (−). (a) False (b) True
  33. 33.🔺 A current of 0.5 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  34. 34.📏 How many amperes (A) is 720 mA? =
  35. 35.🧩 Which component beeps for an alarm? (a) fuse (b) buzzer (c) resistor (d) LED
  36. 36.📏 How many ohms (Ω) is 3.6 kΩ?
  37. 37.🌈 A resistor has the colour bands blue, blue, black. What is its value (in ohms)?
  38. 38.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V × I (d) P = V ÷ I
  39. 39.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water tank lid (b) the pipe colour (c) the tap handle (d) the water pressure
  40. 40.🧮 Five equal 500 Ω resistors are joined in parallel. What is the total resistance (in ohms)?

Answer key

  1. 36000
  2. 0.1
  3. ammeter
  4. 0.2
  5. cathode (−)
  6. energy used each second
  7. 0.5
  8. False
  9. True
  10. 0.5
  11. I = V ÷ R
  12. 3
  13. 780
  14. 40
  15. an LED lamp
  16. 1000
  17. how much a part resists
  18. 230
  19. 1150
  20. LDR
  21. 12
  22. 6
  23. 3
  24. 2
  25. close the fridge quickly
  26. ohm (Ω)
  27. True
  28. less than either one
  29. True
  30. current
  31. 0.25
  32. True
  33. 2
  34. 0.72
  35. buzzer
  36. 3600
  37. 66
  38. P = V × I
  39. the water pressure
  40. 100

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