← 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 964 · 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 component limits the current? (a) LED (b) fuse (c) buzzer (d) resistor
  2. 2.📏 How many amperes (A) is 220 mA? =
  3. 3.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) bigger (c) smaller (d) zero
  4. 4.🔺 A current of 40 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  5. 5.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
  6. 6.🔍 Which is the odd one out? (a) leave the TV on standby (b) leave fridge door open (c) iron one shirt at a time (d) set the AC to 24 °C
  7. 7.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
  8. 8.💡 Why does an LED need a resistor in series? (a) to store charge (b) to limit the current (c) to change its colour (d) to make it brighter
  9. 9.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  10. 10.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  11. 11.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 2.75 V supply. What current flows (in mA)?
  12. 12.Which of these wastes electricity? (a) leave fridge door open (b) set the AC to 24 °C (c) use daylight to read (d) unplug idle chargers
  13. 13.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
  14. 14.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  15. 15.⚡ A device works on 3 V and takes 0.1 A. What is its power (in watts)? =
  16. 16.🔺 A current of 3 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  17. 17.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  18. 18.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = I ÷ V (c) R = V + I (d) R = V ÷ I
  19. 19.🌈 In the resistor colour code, which number does brown stand for?
  20. 20.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets smaller (c) gets bigger (d) becomes zero
  21. 21.⚡ Power tells us … (a) the colour of light (b) energy used each second (c) the size of a cell (d) the length of a wire
  22. 22.🔺 A current of 20 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  23. 23.🔺 A current of 10 mA flows when 3.3 V is joined across a resistor. What is its resistance (in ohms)?
  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 7 hours. How many watt-hours (Wh) are saved?
  25. 25.Which of these saves electricity? (a) iron one shirt at a time (b) switch off empty rooms (c) use old filament bulbs (d) leave the TV on standby
  26. 26.🧩 Which component senses how hot it is? (a) thermistor (b) potentiometer (c) buzzer (d) LDR
  27. 27.🧮 A 22 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  28. 28.🧮 Five equal 500 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  29. 29.🔺 A 5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  30. 30.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
  31. 31.🔺 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
  32. 32.🔺 A current of 0.2 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.🔺 A current of 1.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.🧾 One “unit” on an electricity bill is … (a) 1 kilowatt-hour (kWh) (b) 1 volt (c) 1 ampere (d) 1 watt
  35. 35.💡 A red LED uses 2 V and should get 10 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
  36. 36.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
  37. 37.🔺 A current of 0.2 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.🔺 A current of 40 mA flows when 8.8 V is joined across a resistor. What is its resistance (in ohms)?
  39. 39.🌈 A resistor has the colour bands yellow, green, red. What is its value (in ohms)?
  40. 40.🧮 Resistors of 50 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?

Answer key

  1. resistor
  2. 0.22
  3. bigger
  4. 4
  5. 300
  6. set the AC to 24 °C
  7. saves electricity
  8. to limit the current
  9. cathode (−)
  10. cathode (−)
  11. 5
  12. leave fridge door open
  13. 345
  14. anode (+)
  15. 0.3
  16. 2
  17. 165
  18. R = V ÷ I
  19. 1
  20. gets smaller
  21. energy used each second
  22. 8
  23. 330
  24. 441
  25. switch off empty rooms
  26. thermistor
  27. 27
  28. 100
  29. 50
  30. wastes electricity
  31. I = V ÷ R
  32. 1.2
  33. 4.5
  34. 1 kilowatt-hour (kWh)
  35. 700
  36. saves electricity
  37. 3
  38. 220
  39. 4500
  40. 100

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