← Part 2 test: components and Ohm’s law lesson New set →

Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 825 · 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.True or false: power is measured in ohms (Ω). (a) False (b) True
  2. 2.📏 How many watts (W) is 0.4 kW?
  3. 3.⚡ Power tells us … (a) the colour of light (b) the length of a wire (c) the size of a cell (d) energy used each second
  4. 4.⚡ A 1.2 W device works on 12 V. What current does it take (in amperes)? =
  5. 5.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  6. 6.🔺 A 30 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  7. 7.📏 In the water-pipe picture of a circuit, current is like … (a) the water pressure (b) a narrow pipe (c) the pipe colour (d) the flow of water
  8. 8.🧾 One “unit” on an electricity bill is … (a) 1 kilowatt-hour (kWh) (b) 1 ampere (c) 1 volt (d) 1 watt
  9. 9.🧮 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
  10. 10.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
  11. 11.⚡ A device works on 1.5 V and takes 0.2 A. What is its power (in watts)? =
  12. 12.🔺 A 3.75 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  13. 13.🔺 A current of 1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  14. 14.🌈 Which band is read first on a resistor? (a) the widest gap (b) any band (c) the one nearest an end (d) the gold band
  15. 15.🌈 A resistor has the colour bands white, yellow, black. What is its value (in ohms)?
  16. 16.🔺 A 0.8 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  17. 17.🔺 A current of 40 mA flows when 8.8 V is joined across a resistor. What is its resistance (in ohms)?
  18. 18.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
  19. 19.🌈 A resistor has the colour bands white, grey, black. What is its value (in ohms)?
  20. 20.🔺 A 2.5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  21. 21.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
  22. 22.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water tank lid (b) the water pressure (c) the tap handle (d) the pipe colour
  23. 23.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  24. 24.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
  25. 25.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = V × R (c) I = R ÷ V (d) I = V + R
  26. 26.🔺 A current of 2.5 A flows when 37.5 V is joined across a resistor. What is its resistance (in ohms)?
  27. 27.🔺 A 10 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  28. 28.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
  29. 29.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  30. 30.🧾 A 500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  31. 31.True or false: on an LED, the round-side leg is the cathode (−). (a) False (b) True
  32. 32.💡 An LED is joined to a 9 V battery with no resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) lights up (b) does not light (c) may burn out
  33. 33.🧮 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)?
  34. 34.True or false: to use LED lamps wastes electricity. (a) True (b) False
  35. 35.🔺 An 8 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  36. 36.🔺 A current of 0.1 A flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
  37. 37.🔺 An 8 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  38. 38.🧮 Resistors of 470 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
  39. 39.💡 An LED is joined to a 5 V battery through a 1000 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) may burn out (b) does not light (c) lights up
  40. 40.🧩 Which component glows using little power? (a) capacitor (b) LED (c) resistor (d) motor

Answer key

  1. False
  2. 400
  3. energy used each second
  4. 0.1
  5. 50
  6. 1.5
  7. the flow of water
  8. 1 kilowatt-hour (kWh)
  9. less than either one
  10. True
  11. 0.3
  12. 0.25
  13. 10
  14. the one nearest an end
  15. 94
  16. 0.1
  17. 220
  18. wastes electricity
  19. 98
  20. 10
  21. 204
  22. the water pressure
  23. cathode (−)
  24. 189
  25. I = V ÷ R
  26. 15
  27. 0.5
  28. voltmeter
  29. anode (+)
  30. 1
  31. False
  32. may burn out
  33. 320
  34. False
  35. 40
  36. 15
  37. 2
  38. 620
  39. lights up
  40. LED

Free electronics lessons, practice and worksheets at talentjr.in/electronics-for-kids