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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 619 · 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.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 82 Ω resistor? (a) red-grey-black (b) grey-red-black (c) white-red-black (d) grey-red-brown
  2. 2.🧾 A 250 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  3. 3.True or false: an LDR stores a little charge. (a) True (b) False
  4. 4.⚡ A device works on 3 V and takes 0.2 A. What is its power (in watts)? =
  5. 5.🌈 In the resistor colour code, which number does black stand for?
  6. 6.📏 In the water-pipe picture of a circuit, voltage is like … (a) the pipe colour (b) the water tank lid (c) the tap handle (d) the water pressure
  7. 7.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a resistor (c) a capacitor (d) a diode
  8. 8.🧾 A 100 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
  9. 9.🧮 Four equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  10. 10.What does a potentiometer do? (a) is a resistance knob (b) blows if current is high (c) has coloured bands (d) turns a fan or wheels
  11. 11.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  12. 12.🔺 A current of 25 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
  13. 13.True or false: a fuse beeps for an alarm. (a) True (b) False
  14. 14.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = I ÷ V (c) P = V × I (d) P = V + I
  15. 15.💡 A red LED uses 2 V and should get 20 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
  16. 16.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
  17. 17.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 volt (c) 1 ampere (d) 1 kilowatt-hour (kWh)
  18. 18.True or false: to switch off empty rooms wastes electricity. (a) True (b) False
  19. 19.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 44000 Ω resistor? (a) yellow-yellow-orange (b) yellow-yellow-yellow (c) yellow-yellow-red (d) yellow-green-orange
  20. 20.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
  21. 21.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = I ÷ V (c) R = V + I (d) R = V ÷ I
  22. 22.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  23. 23.🌈 Which band is read first on a resistor? (a) the widest gap (b) the one nearest an end (c) any band (d) the gold band
  24. 24.🧮 A 6 V battery is joined to 2 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
  25. 25.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 3100 Ω resistor? (a) brown-orange-red (b) orange-brown-brown (c) orange-brown-orange (d) orange-brown-red
  26. 26.⚡ A device works on 1.5 V and takes 3 A. What is its power (in watts)? =
  27. 27.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
  28. 28.🧾 A family uses 70 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
  29. 29.🧩 Which component lets current go one way? (a) buzzer (b) diode (c) transistor (d) fuse
  30. 30.🔺 A 16 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  31. 31.🧾 A 50 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  32. 32.🔺 A 1.2 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  33. 33.🔺 A current of 50 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.💡 What does LED stand for? (a) large electric dial (b) light energy dial (c) low energy device (d) light-emitting diode
  35. 35.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
  36. 36.🔺 A current of 20 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an oil lamp (c) a candle (d) an LED lamp
  38. 38.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I + R (c) V = I ÷ R (d) V = I × R
  39. 39.True or false: a potentiometer makes a beeping sound. (a) False (b) True
  40. 40.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?

Answer key

  1. grey-red-black
  2. 2.5
  3. False
  4. 0.6
  5. 0
  6. the water pressure
  7. a buzzer
  8. 0.5
  9. 5
  10. is a resistance knob
  11. cathode (−)
  12. 11.75
  13. False
  14. P = V × I
  15. 500
  16. 1150
  17. 1 kilowatt-hour (kWh)
  18. False
  19. yellow-yellow-orange
  20. 920
  21. R = V ÷ I
  22. 10
  23. the one nearest an end
  24. 1
  25. orange-brown-red
  26. 4.5
  27. ammeter
  28. 490
  29. diode
  30. 40
  31. 0.5
  32. 10
  33. 16.5
  34. light-emitting diode
  35. 204
  36. 9.4
  37. an LED lamp
  38. V = I × R
  39. False
  40. 230

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