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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 181 · 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.🔺 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
  2. 2.🔺 A current of 2.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
  4. 4.True or false: a buzzer stores a little charge. (a) False (b) True
  5. 5.True or false: a resistor limits the current. (a) True (b) False
  6. 6.🔺 A current of 1 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
  7. 7.💡 An LED is joined to a 6 V battery through a 330 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
  8. 8.📏 Which unit measures energy used each second? (a) watt (W) (b) ohm (Ω) (c) ampere (A) (d) volt (V)
  9. 9.True or false: the voltmeter measures current. (a) False (b) True
  10. 10.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 kilowatt-hour (kWh) (c) 1 watt (d) 1 ampere
  11. 11.🔺 A 13.2 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  12. 12.🌈 A resistor has the colour bands orange, green, red. What is its value in kilo-ohms (kΩ)? =
  13. 13.🧮 Resistors of 20 Ω, 22 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
  14. 14.⚡ A device works on 3 V and takes 0.5 A. What is its power (in watts)? =
  15. 15.True or false: the ammeter is joined in series. (a) False (b) True
  16. 16.🧾 A family uses 120 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
  17. 17.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
  18. 18.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 9800 Ω resistor? (a) grey-white-red (b) white-grey-brown (c) white-grey-orange (d) white-grey-red
  19. 19.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  20. 20.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  21. 21.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  22. 22.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = I ÷ R (c) V = R ÷ I (d) V = I + R
  23. 23.🧾 A family uses 40 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  24. 24.💡 What does LED stand for? (a) light-emitting diode (b) large electric dial (c) light energy dial (d) low energy device
  25. 25.⚡ A 3 W device works on 3 V. What current does it take (in amperes)? =
  26. 26.🔺 A current of 0.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  27. 27.🔺 A 0.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  28. 28.Which of these is measured in amperes (A)? (a) energy used each second (b) power (c) current (d) the push of a cell
  29. 29.True or false: to switch off empty rooms saves electricity. (a) True (b) False
  30. 30.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 0 % (c) 5 % (d) 25 %
  31. 31.🌈 A resistor has the colour bands orange, brown, red. What is its value in kilo-ohms (kΩ)? =
  32. 32.🌈 A resistor has the colour bands yellow, violet, yellow. What is its value in kilo-ohms (kΩ)? =
  33. 33.🧾 A 50 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  34. 34.💡 Why does an LED need a resistor in series? (a) to store charge (b) to make it brighter (c) to change its colour (d) to limit the current
  35. 35.📏 Which unit measures voltage? (a) volt (V) (b) ampere (A) (c) watt (W) (d) ohm (Ω)
  36. 36.📏 How many milliamperes (mA) make 1 ampere? (a) 1000 (b) 100 (c) 10 (d) 60
  37. 37.🔺 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
  38. 38.🧮 A 470 Ω resistor is joined in series with two equal 330 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  39. 39.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 12000 Ω resistor? (a) brown-red-orange (b) brown-red-yellow (c) brown-red-red (d) red-brown-orange
  40. 40.⚡ 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

Answer key

  1. I = V ÷ R
  2. 7.5
  3. 306
  4. False
  5. True
  6. 12
  7. does not light
  8. watt (W)
  9. False
  10. 1 kilowatt-hour (kWh)
  11. 40
  12. 3.5
  13. 52
  14. 1.5
  15. True
  16. 840
  17. voltmeter
  18. white-grey-red
  19. cathode (−)
  20. cathode (−)
  21. 50
  22. V = I × R
  23. 160
  24. light-emitting diode
  25. 1
  26. 7.5
  27. 0.1
  28. current
  29. True
  30. 5 %
  31. 3.1
  32. 470
  33. 0.5
  34. to limit the current
  35. volt (V)
  36. 1000
  37. R = V ÷ I
  38. 635
  39. brown-red-orange
  40. energy used each second

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