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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 607 · 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.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) more than either one (c) their sum (d) always zero
  2. 2.🧾 A family uses 110 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
  3. 3.🔺 A current of 20 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
  4. 4.🧩 Which component blows if current is high? (a) buzzer (b) fuse (c) potentiometer (d) diode
  5. 5.🧮 A 20 Ω resistor is joined in series with two equal 20 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  6. 6.🔺 A current of 25 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
  7. 7.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
  8. 8.True or false: to leave the TV on standby saves electricity. (a) True (b) False
  9. 9.📏 How many ohms (Ω) is 0.3 kΩ?
  10. 10.True or false: a potentiometer makes things spin. (a) True (b) False
  11. 11.💡 Why does an LED need a resistor in series? (a) to store charge (b) to make it brighter (c) to limit the current (d) to change its colour
  12. 12.True or false: a fuse blows if current is high. (a) False (b) True
  13. 13.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 3.5 V supply. What current flows (in mA)?
  14. 14.🔺 A 4 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  15. 15.🌈 A resistor has the colour bands orange, brown, red. What is its value (in ohms)?
  16. 16.🧾 A family uses 70 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
  17. 17.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 4 V supply. What current flows (in mA)?
  18. 18.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 25 % (c) 50 % (d) 5 %
  19. 19.🔺 A current of 0.1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  20. 20.💡 What does LED stand for? (a) light energy dial (b) large electric dial (c) light-emitting diode (d) low energy device
  21. 21.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
  22. 22.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 91000 Ω resistor? (a) white-brown-orange (b) brown-white-orange (c) white-brown-red (d) white-brown-yellow
  23. 23.🔺 A current of 40 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  24. 24.🔺 A 9 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  25. 25.🌈 A resistor has the colour bands violet, blue, orange. What is its value (in ohms)?
  26. 26.💡 An LED is joined to a 5 V battery through a 1000 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) lights up (b) may burn out (c) does not light
  27. 27.🧮 A 220 Ω resistor is joined in series with two equal 200 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  28. 28.🌈 In the resistor colour code, which number does black stand for?
  29. 29.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = I ÷ V (c) P = V + I (d) P = V × I
  30. 30.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
  31. 31.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 10 hours. How many watt-hours (Wh) are saved?
  32. 32.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
  33. 33.🧩 Which part changes electrical energy into movement? (a) an LED (b) a resistor (c) a fuse (d) a motor
  34. 34.Which of these is measured in watts (W)? (a) the flow of charge (b) resistance (c) energy used each second (d) the push of a cell
  35. 35.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
  36. 36.⚡ A device works on 5 V and takes 0.25 A. What is its power (in watts)? =
  37. 37.Which of these is measured in volts (V)? (a) power (b) current (c) how much a part resists (d) voltage
  38. 38.🧾 A family uses 20 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  39. 39.🔺 A current of 3 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  40. 40.🔺 A current of 40 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?

Answer key

  1. less than either one
  2. 880
  3. 10
  4. fuse
  5. 30
  6. 11.75
  7. 567
  8. False
  9. 300
  10. False
  11. to limit the current
  12. True
  13. 10
  14. 0.2
  15. 3100
  16. 490
  17. 20
  18. 5 %
  19. 1
  20. light-emitting diode
  21. ammeter
  22. white-brown-orange
  23. 6
  24. 3
  25. 76000
  26. does not light
  27. 320
  28. 0
  29. P = V × I
  30. voltmeter
  31. 510
  32. 1150
  33. a motor
  34. energy used each second
  35. 765
  36. 1.25
  37. voltage
  38. 80
  39. 2
  40. 200

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