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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 317 · 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.🌈 In the resistor colour code, which number does violet stand for?
  2. 2.Which of these saves electricity? (a) iron one shirt at a time (b) set the AC to 24 °C (c) run fans in empty rooms (d) use old filament bulbs
  3. 3.💡 An LED is joined to a 12 V battery with no resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) lights up (b) may burn out (c) does not light
  4. 4.🔺 A 6 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
  5. 5.What does a resistor do? (a) smooths a wobbly supply (b) lets current go one way (c) glows using little power (d) limits the current
  6. 6.🧾 A 100 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
  7. 7.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it makes a sound (c) it changes colour (d) it does not light
  8. 8.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
  9. 9.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
  10. 10.🌈 A resistor has the colour bands white, orange, black. What is its value (in ohms)?
  11. 11.🔺 A current of 40 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  12. 12.⚡ A 0.6 W device works on 3 V. What current does it take (in amperes)? =
  13. 13.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  14. 14.🔺 A 0.2 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  15. 15.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  16. 16.🔺 A 9 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  17. 17.🔺 A current of 0.5 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  18. 18.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  19. 19.True or false: an LED has coloured bands. (a) True (b) False
  20. 20.🌈 A resistor has the colour bands blue, white, orange. What is its value in kilo-ohms (kΩ)? =
  21. 21.⚡ A device works on 6 V and takes 0.2 A. What is its power (in watts)? =
  22. 22.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the widest gap (c) any band (d) the gold band
  23. 23.True or false: the voltmeter is joined across a part. (a) False (b) True
  24. 24.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 0 % (c) 25 % (d) 5 %
  25. 25.🔍 Which is the odd one out? (a) use daylight to read (b) unplug idle chargers (c) set the AC to 24 °C (d) use old filament bulbs
  26. 26.🧮 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)?
  27. 27.🧮 A 2.25 V battery is joined to 5 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
  28. 28.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
  29. 29.🌈 A resistor has the colour bands brown, grey, yellow. What is its value in kilo-ohms (kΩ)? =
  30. 30.🌈 A resistor has the colour bands brown, black, brown. What is its value (in ohms)?
  31. 31.📏 In the water-pipe picture of a circuit, current is like … (a) a narrow pipe (b) the water pressure (c) the flow of water (d) the pipe colour
  32. 32.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 75 Ω resistor? (a) grey-green-black (b) green-violet-black (c) violet-green-brown (d) violet-green-black
  33. 33.True or false: the ammeter measures voltage. (a) False (b) True
  34. 34.🔺 A current of 2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  36. 36.True or false: the voltmeter measures voltage. (a) True (b) False
  37. 37.True or false: a capacitor stores a little charge. (a) True (b) False
  38. 38.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
  39. 39.🔺 A current of 10 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) switch off empty rooms (c) use LED lamps (d) leave the TV on standby

Answer key

  1. 7
  2. set the AC to 24 °C
  3. may burn out
  4. 20
  5. limits the current
  6. 0.8
  7. it does not light
  8. wastes electricity
  9. 345
  10. 93
  11. 100
  12. 0.2
  13. 20
  14. 0.1
  15. 5
  16. 1.5
  17. 12
  18. anode (+)
  19. False
  20. 69
  21. 1.2
  22. the one nearest an end
  23. True
  24. 5 %
  25. use old filament bulbs
  26. 38
  27. 0.25
  28. 255
  29. 180
  30. 100
  31. the flow of water
  32. violet-green-black
  33. False
  34. 6
  35. 165
  36. True
  37. True
  38. False
  39. 3
  40. leave the TV on standby

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