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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 314 · 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.🧮 Resistors of 47 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
  2. 2.🧮 Two equal 220 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  3. 3.🔺 A 4 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  4. 4.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  5. 5.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V + I (c) R = V ÷ I (d) R = V × I
  6. 6.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = R ÷ V (c) I = V × R (d) I = V + R
  7. 7.📏 Which unit measures current? (a) volt (V) (b) watt (W) (c) ampere (A) (d) ohm (Ω)
  8. 8.📏 Which unit measures the flow of charge? (a) ohm (Ω) (b) volt (V) (c) ampere (A) (d) watt (W)
  9. 9.🧮 Two equal 10 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  10. 10.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  11. 11.🧮 Resistors of 20 Ω, 470 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
  12. 12.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
  13. 13.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 6 hours. How many watt-hours (Wh) are saved?
  14. 14.🔺 A current of 2.5 A flows when 30 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.🔺 A current of 40 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  16. 16.🧾 A family uses 160 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
  17. 17.🔺 A current of 0.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.🧩 Which part changes electrical energy into movement? (a) a motor (b) a fuse (c) an LED (d) a resistor
  19. 19.🌈 A resistor has the colour bands red, blue, black. What is its value (in ohms)?
  20. 20.🧮 Resistors of 50 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
  21. 21.🧩 Which component makes a beeping sound? (a) transistor (b) motor (c) buzzer (d) potentiometer
  22. 22.💡 A blue LED uses 3 V and should get 25 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
  23. 23.🔺 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
  24. 24.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) bigger (c) smaller (d) stay the same
  25. 25.🔺 A 12.5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  26. 26.⚡ A device works on 1.5 V and takes 1.5 A. What is its power (in watts)? =
  27. 27.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
  28. 28.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 71000 Ω resistor? (a) violet-brown-yellow (b) brown-violet-orange (c) violet-brown-red (d) violet-brown-orange
  29. 29.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 25 % (c) 50 % (d) 5 %
  30. 30.🔺 A 20 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
  31. 31.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 2.5 V supply. What current flows (in mA)?
  32. 32.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets smaller (c) becomes zero (d) gets bigger
  33. 33.📏 Which unit measures the push of a cell? (a) ohm (Ω) (b) ampere (A) (c) watt (W) (d) volt (V)
  34. 34.Which of these is measured in ohms (Ω)? (a) resistance (b) the flow of charge (c) the push of a cell (d) voltage
  35. 35.🔺 A 2.5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  36. 36.📏 How many ohms (Ω) is 4 kΩ?
  37. 37.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  38. 38.🌈 A resistor has the colour bands green, orange, red. What is its value in kilo-ohms (kΩ)? =
  39. 39.🌈 A resistor has the colour bands brown, brown, red. What is its value (in ohms)?
  40. 40.⚡ A device works on 6 V and takes 0.25 A. What is its power (in watts)? =

Answer key

  1. 57
  2. 110
  3. 40
  4. cathode (−)
  5. R = V ÷ I
  6. I = V ÷ R
  7. ampere (A)
  8. ampere (A)
  9. 5
  10. 4
  11. 558
  12. wastes electricity
  13. 306
  14. 12
  15. 13.2
  16. 800
  17. 1
  18. a motor
  19. 26
  20. 150
  21. buzzer
  22. 240
  23. V = I × R
  24. bigger
  25. 50
  26. 2.25
  27. ammeter
  28. violet-brown-orange
  29. 5 %
  30. 40
  31. 5
  32. gets smaller
  33. volt (V)
  34. resistance
  35. 10
  36. 4000
  37. anode (+)
  38. 5.3
  39. 1100
  40. 1.5

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