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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 92 · 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 family uses 140 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  2. 2.🔺 A current of 1 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
  4. 4.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  5. 5.🔺 A current of 25 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  6. 6.📏 How many kilo-ohms (kΩ) is 8900 Ω? =
  7. 7.🔺 A current of 25 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.🔺 A current of 40 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  9. 9.🔺 A current of 20 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  10. 10.🌈 In the resistor colour code, which number does white stand for?
  11. 11.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
  12. 12.💡 A red LED uses 2 V and should get 20 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
  13. 13.True or false: a diode lets current go one way. (a) False (b) True
  14. 14.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
  15. 15.📏 Which unit measures resistance? (a) watt (W) (b) ampere (A) (c) ohm (Ω) (d) volt (V)
  16. 16.True or false: a thermistor beeps for an alarm. (a) False (b) True
  17. 17.🔺 A 5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  18. 18.🌈 Which band is read first on a resistor? (a) the widest gap (b) the gold band (c) any band (d) the one nearest an end
  19. 19.🌈 In the resistor colour code, which number does black stand for?
  20. 20.True or false: energy used each second is measured in watts (W). (a) True (b) False
  21. 21.📏 How many ohms (Ω) is 0.1 kΩ?
  22. 22.📏 How many kilowatts (kW) is 350 W? =
  23. 23.🧮 Four equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  24. 24.⚡ Power tells us … (a) energy used each second (b) the length of a wire (c) the size of a cell (d) the colour of light
  25. 25.⚡ Which formula gives electric power? (a) P = V × I (b) P = V + I (c) P = I ÷ V (d) P = V ÷ I
  26. 26.🔺 A current of 3 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  27. 27.True or false: to use old filament bulbs saves electricity. (a) False (b) True
  28. 28.🔺 A current of 25 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
  29. 29.🌈 In the resistor colour code, which number does orange stand for?
  30. 30.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 57000 Ω resistor? (a) green-violet-yellow (b) violet-green-orange (c) green-violet-orange (d) green-violet-red
  31. 31.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) becomes zero (c) stays the same (d) gets smaller
  32. 32.🔺 A current of 0.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  34. 34.🔍 Which is the odd one out? (a) leave fridge door open (b) switch off empty rooms (c) run fans in empty rooms (d) use old filament bulbs
  35. 35.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
  36. 36.True or false: a transistor boosts a small signal. (a) True (b) False
  37. 37.⚡ A 36 W device works on 24 V. What current does it take (in amperes)? =
  38. 38.Which of these saves electricity? (a) run fans in empty rooms (b) use LED lamps (c) leave the TV on standby (d) use old filament bulbs
  39. 39.📏 In the water-pipe picture of a circuit, current is like … (a) the water pressure (b) the flow of water (c) the pipe colour (d) a narrow pipe
  40. 40.🔍 Which is the odd one out? (a) close the fridge quickly (b) leave the TV on standby (c) iron one shirt at a time (d) run fans in empty rooms

Answer key

  1. 560
  2. 8
  3. 1150
  4. cathode (−)
  5. 3.75
  6. 8.9
  7. 10
  8. 6
  9. 4
  10. 9
  11. saves electricity
  12. 200
  13. True
  14. saves electricity
  15. ohm (Ω)
  16. False
  17. 20
  18. the one nearest an end
  19. 0
  20. True
  21. 100
  22. 0.35
  23. 10
  24. energy used each second
  25. P = V × I
  26. 60
  27. False
  28. 12.5
  29. 3
  30. green-violet-orange
  31. gets smaller
  32. 2.5
  33. anode (+)
  34. switch off empty rooms
  35. ammeter
  36. True
  37. 1.5
  38. use LED lamps
  39. the flow of water
  40. close the fridge quickly

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