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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 620 · 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 resistor has the colour bands violet, blue, yellow. What is its value in kilo-ohms (kΩ)? =
  2. 2.📏 In the water-pipe picture of a circuit, voltage is like … (a) the pipe colour (b) the water pressure (c) the tap handle (d) the water tank lid
  3. 3.⚡ A 36 W device works on 24 V. What current does it take (in amperes)? =
  4. 4.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 5 V supply. What current flows (in mA)?
  5. 5.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it makes a sound (c) it does not light (d) it changes colour
  6. 6.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 350 Ω resistor? (a) orange-green-black (b) orange-green-red (c) orange-green-brown (d) green-orange-brown
  7. 7.🌈 A resistor has the colour bands blue, green, orange. What is its value in kilo-ohms (kΩ)? =
  8. 8.🌈 A resistor has the colour bands brown, yellow, brown. What is its value (in ohms)?
  9. 9.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 41000 Ω resistor? (a) brown-yellow-orange (b) yellow-brown-yellow (c) yellow-brown-red (d) yellow-brown-orange
  10. 10.🌈 In the resistor colour code, which number does green stand for?
  11. 11.🔺 A current of 1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  12. 12.🔺 A current of 40 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  13. 13.🌈 A resistor has the colour bands blue, blue, red. What is its value (in ohms)?
  14. 14.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V × I (d) P = V ÷ I
  15. 15.🧾 A family uses 40 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  16. 16.⚡ A device works on 3 V and takes 0.1 A. What is its power (in watts)? =
  17. 17.True or false: the flow of charge is measured in volts (V). (a) True (b) False
  18. 18.True or false: to run fans in empty rooms saves electricity. (a) True (b) False
  19. 19.🔺 A current of 25 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  20. 20.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 60 Ω resistor? (a) violet-black-black (b) violet-blue-black (c) blue-black-brown (d) blue-black-black
  21. 21.📏 In the water-pipe picture of a circuit, resistance is like … (a) a narrow pipe (b) the water pressure (c) the flow of water (d) a bigger tank
  22. 22.🧩 Which component makes things spin? (a) motor (b) diode (c) buzzer (d) fuse
  23. 23.🧮 A 10 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)?
  24. 24.What does a diode do? (a) lets current go one way (b) makes a beeping sound (c) beeps for an alarm (d) makes things spin
  25. 25.🔺 A 1.5 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  26. 26.🔍 Which is the odd one out? (a) leave fridge door open (b) switch off empty rooms (c) use daylight to read (d) unplug idle chargers
  27. 27.🔺 A current of 0.1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  28. 28.Which of these saves electricity? (a) iron one shirt at a time (b) switch off empty rooms (c) run fans in empty rooms (d) leave fridge door open
  29. 29.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  30. 30.🧾 A 1500 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
  31. 31.Which of these wastes electricity? (a) set the AC to 24 °C (b) use LED lamps (c) run fans in empty rooms (d) switch off empty rooms
  32. 32.🧩 A capacitor in a circuit can … (a) store charge briefly (b) spin a wheel (c) measure heat (d) make light
  33. 33.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = I ÷ R (c) V = I × R (d) V = R ÷ I
  34. 34.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
  35. 35.⚡ Power tells us … (a) the colour of light (b) energy used each second (c) the size of a cell (d) the length of a wire
  36. 36.🔺 A current of 3 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.💡 An LED is joined to a 3 V battery through a 330 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) may burn out (c) lights up
  38. 38.🔺 A current of 0.25 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  39. 39.💡 An LED is joined to a 3 V battery through a 220 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) may burn out (b) does not light (c) lights up
  40. 40.📏 How many kilowatts (kW) is 3350 W? =

Answer key

  1. 760
  2. the water pressure
  3. 1.5
  4. 20
  5. it does not light
  6. orange-green-brown
  7. 65
  8. 140
  9. yellow-brown-orange
  10. 5
  11. 10
  12. 8.8
  13. 6600
  14. P = V × I
  15. 160
  16. 0.3
  17. False
  18. False
  19. 5.5
  20. blue-black-black
  21. a narrow pipe
  22. motor
  23. 35
  24. lets current go one way
  25. 0.5
  26. leave fridge door open
  27. 0.2
  28. switch off empty rooms
  29. cathode (−)
  30. 7.5
  31. run fans in empty rooms
  32. store charge briefly
  33. V = I × R
  34. False
  35. energy used each second
  36. 6
  37. lights up
  38. 1.25
  39. lights up
  40. 3.35

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