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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 336 · 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.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
  2. 2.🔺 A current of 1.5 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
  3. 3.🧮 A 10 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)?
  4. 4.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  5. 5.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  6. 6.🧮 Three equal 30 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  7. 7.True or false: a fuse smooths a wobbly supply. (a) True (b) False
  8. 8.💡 What happens if an LED is put in backwards? (a) it does not light (b) it changes colour (c) it makes a sound (d) it lights brighter
  9. 9.True or false: to run fans in empty rooms wastes electricity. (a) False (b) True
  10. 10.⚡ A device works on 24 V and takes 1 A. What is its power (in watts)? =
  11. 11.📏 In the water-pipe picture of a circuit, voltage is like … (a) the tap handle (b) the water tank lid (c) the water pressure (d) the pipe colour
  12. 12.🔺 A current of 20 mA flows when 9.4 V is joined across a resistor. What is its resistance (in ohms)?
  13. 13.🧩 A capacitor in a circuit can … (a) store charge briefly (b) spin a wheel (c) measure heat (d) make light
  14. 14.🧮 Resistors of 100 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
  15. 15.🔍 Which is the odd one out? (a) leave fridge door open (b) set the AC to 24 °C (c) use old filament bulbs (d) run fans in empty rooms
  16. 16.🧮 A 20 Ω resistor is joined in series with two equal 40 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  17. 17.Which of these is measured in ohms (Ω)? (a) the push of a cell (b) resistance (c) voltage (d) energy used each second
  18. 18.📏 How many kilo-ohms (kΩ) is 2400 Ω? =
  19. 19.🔍 Which is the odd one out? (a) leave fridge door open (b) use old filament bulbs (c) run fans in empty rooms (d) unplug idle chargers
  20. 20.🔺 A current of 0.1 A flows when 0.3 V is joined across a resistor. What is its resistance (in ohms)?
  21. 21.🧮 Two equal 10 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  22. 22.Which of these is measured in volts (V)? (a) resistance (b) how much a part resists (c) current (d) voltage
  23. 23.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 31000 Ω resistor? (a) orange-brown-red (b) orange-brown-orange (c) brown-orange-orange (d) orange-brown-yellow
  24. 24.🧮 An 8 V battery is joined to 3 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
  25. 25.⚡ An 18 W device works on 12 V. What current does it take (in amperes)? =
  26. 26.🔺 A current of 10 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  27. 27.🧮 A 1.1 V battery is joined to 3 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
  28. 28.⚡ Power tells us … (a) the length of a wire (b) the colour of light (c) energy used each second (d) the size of a cell
  29. 29.🧩 Which component makes things spin? (a) LED (b) motor (c) resistor (d) thermistor
  30. 30.🔍 Which is the odd one out? (a) unplug idle chargers (b) use LED lamps (c) use daylight to read (d) run fans in empty rooms
  31. 31.🌈 A resistor has the colour bands blue, black, black. What is its value (in ohms)?
  32. 32.True or false: a buzzer has coloured bands. (a) False (b) True
  33. 33.What does a thermistor do? (a) stores a little charge (b) smooths a wobbly supply (c) senses how hot it is (d) blows if current is high
  34. 34.🧮 A 0.5 V battery is joined to 2 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
  35. 35.True or false: on an LED, the round-side leg is the cathode (−). (a) False (b) True
  36. 36.🔺 A current of 1.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.🔺 A current of 0.1 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.💡 An LED is joined to a 3 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) lights up (c) does not light
  39. 39.🔺 A current of 0.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.Which of these is measured in amperes (A)? (a) power (b) how much a part resists (c) voltage (d) the flow of charge

Answer key

  1. 460
  2. 8
  3. 15
  4. cathode (−)
  5. 500
  6. 10
  7. False
  8. it does not light
  9. True
  10. 24
  11. the water pressure
  12. 470
  13. store charge briefly
  14. 133
  15. set the AC to 24 °C
  16. 40
  17. resistance
  18. 2.4
  19. unplug idle chargers
  20. 3
  21. 5
  22. voltage
  23. orange-brown-orange
  24. 1
  25. 1.5
  26. 300
  27. 0.1
  28. energy used each second
  29. motor
  30. run fans in empty rooms
  31. 60
  32. False
  33. senses how hot it is
  34. 0.1
  35. False
  36. 18
  37. 0.6
  38. lights up
  39. 2
  40. the flow of charge

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