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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 174 · 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 2 V battery is joined to 12 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
  2. 2.🔺 A current of 20 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.What does a diode do? (a) has coloured bands (b) blows if current is high (c) turns a fan or wheels (d) lets current go one way
  4. 4.🔺 A current of 20 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  5. 5.🔺 A current of 1.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  6. 6.🧮 A 1.4 V battery is joined to 2 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
  7. 7.🔺 A current of 2 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) their sum (c) more than either one (d) always zero
  9. 9.Which of these saves electricity? (a) leave the TV on standby (b) close the fridge quickly (c) run fans in empty rooms (d) leave fridge door open
  10. 10.🧮 A 0.7 V battery is joined to 2 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
  11. 11.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) smaller (c) stay the same (d) zero
  12. 12.🧾 A 1000 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
  13. 13.📏 In the water-pipe picture of a circuit, resistance is like … (a) a bigger tank (b) the water pressure (c) the flow of water (d) a narrow pipe
  14. 14.🧾 A family uses 40 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  15. 15.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  16. 16.🧮 A 1.8 V battery is joined to 6 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  17. 17.⚡ A device works on 1.5 V and takes 0.2 A. What is its power (in watts)? =
  18. 18.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
  19. 19.🌈 A resistor has the colour bands blue, yellow, red. What is its value in kilo-ohms (kΩ)? =
  20. 20.🔺 A 5.5 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  21. 21.💡 What happens if an LED is put in backwards? (a) it makes a sound (b) it does not light (c) it lights brighter (d) it changes colour
  22. 22.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
  23. 23.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a resistor (c) a motor (d) an LED
  24. 24.🔺 A 2 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  25. 25.True or false: to use LED lamps saves electricity. (a) False (b) True
  26. 26.What does a motor do? (a) boosts a small signal (b) beeps for an alarm (c) turns a fan or wheels (d) smooths a wobbly supply
  27. 27.🌈 A resistor has the colour bands white, green, red. What is its value (in ohms)?
  28. 28.📏 How many amperes (A) is 1290 mA? =
  29. 29.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets smaller (d) gets bigger
  30. 30.True or false: the ammeter measures current. (a) False (b) True
  31. 31.🔺 A current of 0.25 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  32. 32.⚡ A 24 W device works on 12 V. What current does it take (in amperes)? =
  33. 33.True or false: to run fans in empty rooms saves electricity. (a) False (b) True
  34. 34.🔺 A current of 2.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.🧮 Resistors of 20 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
  36. 36.🔺 A current of 25 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.🔍 Which is the odd one out? (a) switch off empty rooms (b) use old filament bulbs (c) leave the TV on standby (d) run fans in empty rooms
  38. 38.⚡ A device works on 1.5 V and takes 0.1 A. What is its power (in watts)? =
  39. 39.🧮 Four equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  40. 40.⚡ Which formula gives electric power? (a) P = V + I (b) P = I ÷ V (c) P = V × I (d) P = V ÷ I

Answer key

  1. 0.1
  2. 6.6
  3. lets current go one way
  4. 2
  5. 9
  6. 0.2
  7. 12
  8. less than either one
  9. close the fridge quickly
  10. 0.1
  11. bigger
  12. 8
  13. a narrow pipe
  14. 160
  15. cathode (−)
  16. 0.1
  17. 0.3
  18. saves electricity
  19. 6.4
  20. 25
  21. it does not light
  22. saves electricity
  23. a motor
  24. 10
  25. True
  26. turns a fan or wheels
  27. 9500
  28. 1.29
  29. gets smaller
  30. True
  31. 0.5
  32. 2
  33. False
  34. 37.5
  35. 88
  36. 12.5
  37. switch off empty rooms
  38. 0.15
  39. 5
  40. P = V × I

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