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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 893 · 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.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) False (b) True
  2. 2.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
  3. 3.True or false: the voltmeter measures current. (a) True (b) False
  4. 4.🌈 In the resistor colour code, which number does red stand for?
  5. 5.🔺 A 4 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  6. 6.🧩 A capacitor in a circuit can … (a) make light (b) measure heat (c) spin a wheel (d) store charge briefly
  7. 7.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 25 % (c) 50 % (d) 0 %
  8. 8.🔺 A 30 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  9. 9.🧮 Resistors of 68 Ω, 150 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
  10. 10.🔺 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
  11. 11.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  12. 12.🧮 A 2 V battery is joined to 3 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
  13. 13.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) smaller (c) zero (d) stay the same
  14. 14.🧮 A 5.5 V battery is joined to 6 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
  15. 15.⚡ Which formula gives electric power? (a) P = V + I (b) P = I ÷ V (c) P = V × I (d) P = V ÷ I
  16. 16.🔺 A 1.5 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  17. 17.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
  18. 18.📏 How many milliamperes (mA) make 1 ampere? (a) 60 (b) 100 (c) 10 (d) 1000
  19. 19.🔺 A 0.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  20. 20.💡 An LED is joined to a 9 V battery with no resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) lights up (c) may burn out
  21. 21.🔺 A current of 40 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  22. 22.🔺 An 8 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  23. 23.🧮 Resistors of 47 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
  24. 24.🧮 A 100 Ω resistor is joined in series with two equal 330 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  25. 25.🧾 A family uses 50 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
  26. 26.🔺 A 1.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  27. 27.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
  28. 28.🔺 A current of 50 mA flows when 23.5 V is joined across a resistor. What is its resistance (in ohms)?
  29. 29.True or false: the voltmeter is joined in series. (a) False (b) True
  30. 30.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  31. 31.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water tank lid (b) the water pressure (c) the pipe colour (d) the tap handle
  32. 32.⚡ A 1.2 W device works on 12 V. What current does it take (in amperes)? =
  33. 33.What does a diode do? (a) blows if current is high (b) senses how bright it is (c) has coloured bands (d) lets current go one way
  34. 34.🔺 A current of 0.2 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  35. 35.🔺 A current of 20 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
  36. 36.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  37. 37.Which of these wastes electricity? (a) switch off empty rooms (b) close the fridge quickly (c) use daylight to read (d) leave fridge door open
  38. 38.Which of these is measured in volts (V)? (a) the push of a cell (b) current (c) resistance (d) the flow of charge
  39. 39.🧮 Resistors of 220 Ω, 20 Ω, 50 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
  40. 40.🌈 A resistor has the colour bands green, black, yellow. What is its value in kilo-ohms (kΩ)? =

Answer key

  1. True
  2. saves electricity
  3. False
  4. 2
  5. 0.2
  6. store charge briefly
  7. 5 %
  8. 3
  9. 238
  10. R = V ÷ I
  11. cathode (−)
  12. 0.25
  13. bigger
  14. 0.5
  15. P = V × I
  16. 0.25
  17. False
  18. 1000
  19. 0.1
  20. may burn out
  21. 8
  22. 40
  23. 80
  24. 265
  25. 250
  26. 10
  27. saves electricity
  28. 470
  29. False
  30. 20
  31. the water pressure
  32. 0.1
  33. lets current go one way
  34. 15
  35. 10
  36. anode (+)
  37. leave fridge door open
  38. the push of a cell
  39. 510
  40. 500

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