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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 668 · 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 4.4 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  2. 2.🧮 Two resistors in parallel give a total that is … (a) always zero (b) more than either one (c) their sum (d) less than either one
  3. 3.🔺 A current of 20 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  4. 4.🔺 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
  5. 5.🔺 A current of 2.5 A flows when 30 V is joined across a resistor. What is its resistance (in ohms)?
  6. 6.🔺 A current of 25 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  7. 7.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V × R (c) I = V + R (d) I = V ÷ R
  8. 8.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
  9. 9.🌈 A resistor has the colour bands violet, white, black. What is its value (in ohms)?
  10. 10.🧾 A family uses 70 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
  11. 11.🧩 Which component limits the current? (a) resistor (b) fuse (c) potentiometer (d) transistor
  12. 12.🔺 A 0.5 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  13. 13.🌈 A resistor has the colour bands brown, blue, black. What is its value (in ohms)?
  14. 14.True or false: on an LED, the longer leg is the cathode (−). (a) False (b) True
  15. 15.🧩 Which component is a resistance knob? (a) capacitor (b) thermistor (c) potentiometer (d) buzzer
  16. 16.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  17. 17.🔺 A current of 0.2 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.Which of these is measured in ohms (Ω)? (a) the flow of charge (b) power (c) energy used each second (d) how much a part resists
  19. 19.📏 In the water-pipe picture of a circuit, voltage is like … (a) the tap handle (b) the water pressure (c) the pipe colour (d) the water tank lid
  20. 20.📏 How many amperes (A) is 1160 mA? =
  21. 21.🔺 A 3 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  22. 22.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  23. 23.🧾 A 50 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  24. 24.🧮 A 22 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)?
  25. 25.🔺 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
  26. 26.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 watt (c) 1 kilowatt-hour (kWh) (d) 1 ampere
  27. 27.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 8000 Ω resistor? (a) grey-black-brown (b) grey-black-red (c) grey-black-orange (d) white-grey-red
  28. 28.🔺 A 3 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  29. 29.🌈 In the resistor colour code, which number does blue stand for?
  30. 30.📏 How many kilo-ohms (kΩ) is 2200 Ω? =
  31. 31.Which of these wastes electricity? (a) close the fridge quickly (b) use LED lamps (c) switch off empty rooms (d) leave fridge door open
  32. 32.True or false: to use LED lamps wastes electricity. (a) False (b) True
  33. 33.True or false: a transistor boosts a small signal. (a) True (b) False
  34. 34.True or false: to leave the TV on standby saves electricity. (a) False (b) True
  35. 35.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) bigger (c) smaller (d) stay the same
  36. 36.🧮 Resistors of 150 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
  37. 37.🧮 Five equal 500 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  38. 38.🧮 A 33 Ω resistor is joined in series with two equal 40 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  39. 39.🧮 Three equal 300 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  40. 40.🔺 A current of 0.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =

Answer key

  1. 20
  2. less than either one
  3. 4
  4. R = V ÷ I
  5. 12
  6. 5
  7. I = V ÷ R
  8. saves electricity
  9. 79
  10. 490
  11. resistor
  12. 0.25
  13. 16
  14. False
  15. potentiometer
  16. anode (+)
  17. 3
  18. how much a part resists
  19. the water pressure
  20. 1.16
  21. 25
  22. 50
  23. 0.1
  24. 187
  25. V = I × R
  26. 1 kilowatt-hour (kWh)
  27. grey-black-red
  28. 20
  29. 6
  30. 2.2
  31. leave fridge door open
  32. False
  33. True
  34. False
  35. bigger
  36. 300
  37. 100
  38. 53
  39. 100
  40. 1.5

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