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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 900 · 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: on an LED, the leg by the flat edge is the anode (+). (a) True (b) False
  2. 2.True or false: the voltmeter measures current. (a) False (b) True
  3. 3.🧩 Which component beeps for an alarm? (a) capacitor (b) resistor (c) thermistor (d) buzzer
  4. 4.📏 Which unit measures energy used each second? (a) ohm (Ω) (b) ampere (A) (c) volt (V) (d) watt (W)
  5. 5.True or false: how much a part resists is measured in ohms (Ω). (a) True (b) False
  6. 6.Which of these saves electricity? (a) run fans in empty rooms (b) leave the TV on standby (c) iron one shirt at a time (d) unplug idle chargers
  7. 7.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
  8. 8.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
  9. 9.🌈 A resistor has the colour bands green, red, orange. What is its value (in ohms)?
  10. 10.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 4400 Ω resistor? (a) yellow-green-red (b) yellow-yellow-brown (c) yellow-yellow-red (d) yellow-yellow-orange
  11. 11.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  12. 12.True or false: on an LED, the shorter leg is the anode (+). (a) True (b) False
  13. 13.🔺 An 18 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  14. 14.🔺 A 2.4 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  15. 15.💡 Why does an LED need a resistor in series? (a) to make it brighter (b) to change its colour (c) to limit the current (d) to store charge
  16. 16.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 46000 Ω resistor? (a) yellow-blue-red (b) yellow-blue-yellow (c) blue-yellow-orange (d) yellow-blue-orange
  17. 17.🔺 A 4 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  18. 18.What does a capacitor do? (a) stores a little charge (b) boosts a small signal (c) turns a fan or wheels (d) beeps for an alarm
  19. 19.⚡ A 0.75 W device works on 1.5 V. What current does it take (in amperes)? =
  20. 20.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
  21. 21.🔺 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
  22. 22.🧩 A capacitor in a circuit can … (a) make light (b) spin a wheel (c) store charge briefly (d) measure heat
  23. 23.🧮 Resistors of 68 Ω, 20 Ω, 330 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
  24. 24.⚡ A device works on 12 V and takes 0.2 A. What is its power (in watts)? =
  25. 25.🔺 A current of 20 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  26. 26.🧮 A 330 Ω resistor is joined in series with two equal 50 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  27. 27.⚡ Power tells us … (a) the size of a cell (b) the length of a wire (c) energy used each second (d) the colour of light
  28. 28.What does a motor do? (a) smooths a wobbly supply (b) senses how bright it is (c) makes things spin (d) limits the current
  29. 29.📏 How many watts (W) is 1.9 kW?
  30. 30.🔺 A current of 0.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  31. 31.🧮 A 22 Ω resistor is joined in series with two equal 200 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  32. 32.🧾 A family uses 180 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
  33. 33.🧮 A 3.25 V battery is joined to 5 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
  34. 34.🔺 A current of 1.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.🔺 A current of 10 mA flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  36. 36.🔺 A 16.5 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  37. 37.🧾 A 250 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
  38. 38.Which of these is measured in volts (V)? (a) the flow of charge (b) voltage (c) power (d) current
  39. 39.🔺 A current of 20 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a motor (c) an LED (d) a resistor

Answer key

  1. False
  2. False
  3. buzzer
  4. watt (W)
  5. True
  6. unplug idle chargers
  7. saves electricity
  8. wastes electricity
  9. 52000
  10. yellow-yellow-red
  11. cathode (−)
  12. False
  13. 1.5
  14. 20
  15. to limit the current
  16. yellow-blue-orange
  17. 0.2
  18. stores a little charge
  19. 0.5
  20. saves electricity
  21. R = V ÷ I
  22. store charge briefly
  23. 638
  24. 2.4
  25. 8
  26. 355
  27. energy used each second
  28. makes things spin
  29. 1900
  30. 1.5
  31. 122
  32. 900
  33. 0.25
  34. 4.5
  35. 100
  36. 50
  37. 1.5
  38. voltage
  39. 4
  40. a motor

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