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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 558 · 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.Which of these is measured in volts (V)? (a) energy used each second (b) current (c) power (d) voltage
  2. 2.🧩 A capacitor in a circuit can … (a) store charge briefly (b) measure heat (c) spin a wheel (d) make light
  3. 3.⚡ 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
  4. 4.🔺 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
  5. 5.🌈 A resistor has the colour bands blue, yellow, orange. What is its value (in ohms)?
  6. 6.True or false: on an LED, the shorter leg is the anode (+). (a) False (b) True
  7. 7.🔺 A current of 10 mA flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.True or false: a capacitor limits the current. (a) True (b) False
  9. 9.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 10 hours. How many watt-hours (Wh) are saved?
  10. 10.🔺 An 8 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  11. 11.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  12. 12.🔺 A current of 20 mA flows when 6.6 V is joined across a resistor. What is its resistance (in ohms)?
  13. 13.💡 An LED is joined to a 5 V battery with no resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) may burn out (b) lights up (c) does not light
  14. 14.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  15. 15.🧮 Two resistors in parallel give a total that is … (a) their sum (b) more than either one (c) less than either one (d) always zero
  16. 16.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
  17. 17.🔺 A 4 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  18. 18.🧩 Which component senses how hot it is? (a) LDR (b) thermistor (c) resistor (d) potentiometer
  19. 19.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V + I (d) P = V × I
  20. 20.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
  21. 21.True or false: the flow of charge is measured in amperes (A). (a) True (b) False
  22. 22.⚡ A device works on 9 V and takes 1 A. What is its power (in watts)? =
  23. 23.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 kilowatt-hour (kWh) (c) 1 volt (d) 1 watt
  24. 24.Which of these is measured in volts (V)? (a) the flow of charge (b) how much a part resists (c) the push of a cell (d) resistance
  25. 25.⚡ A device works on 5 V and takes 3 A. What is its power (in watts)? =
  26. 26.🔺 A current of 0.2 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  27. 27.🔺 A current of 40 mA flows when 13.2 V is joined across a resistor. What is its resistance (in ohms)?
  28. 28.🌈 In the resistor colour code, which number does violet stand for?
  29. 29.🔺 A current of 0.25 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  30. 30.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) False (b) True
  31. 31.🔺 A current of 10 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  32. 32.🧮 Four equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  33. 33.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  34. 34.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) stay the same (c) zero (d) bigger
  35. 35.What does a motor do? (a) senses how hot it is (b) turns a fan or wheels (c) stores a little charge (d) senses how bright it is
  36. 36.📏 How many amperes (A) is 2010 mA? =
  37. 37.🔺 A current of 25 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.📏 How many kilowatts (kW) is 1150 W? =
  39. 39.🌈 A resistor has the colour bands brown, red, red. What is its value in kilo-ohms (kΩ)? =
  40. 40.🧾 A 50 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =

Answer key

  1. voltage
  2. store charge briefly
  3. energy used each second
  4. V = I × R
  5. 64000
  6. False
  7. 100
  8. False
  9. 630
  10. 40
  11. 10
  12. 330
  13. may burn out
  14. cathode (−)
  15. less than either one
  16. 345
  17. 1
  18. thermistor
  19. P = V × I
  20. ammeter
  21. True
  22. 9
  23. 1 kilowatt-hour (kWh)
  24. the push of a cell
  25. 15
  26. 15
  27. 330
  28. 7
  29. 2.5
  30. True
  31. 200
  32. 50
  33. 230
  34. bigger
  35. turns a fan or wheels
  36. 2.01
  37. 2.5
  38. 1.15
  39. 1.2
  40. 0.25

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