← 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 637 · 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 unit measures current? (a) volt (V) (b) ohm (Ω) (c) watt (W) (d) ampere (A)
  2. 2.🧩 Which component stores a little charge? (a) fuse (b) buzzer (c) capacitor (d) thermistor
  3. 3.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
  4. 4.💡 An LED is joined to a 5 V battery through a 330 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) lights up (c) may burn out
  5. 5.🌈 A resistor has the colour bands red, white, brown. What is its value (in ohms)?
  6. 6.True or false: a motor smooths a wobbly supply. (a) True (b) False
  7. 7.⚡ 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
  8. 8.⚡ Which formula gives electric power? (a) P = V + I (b) P = V × I (c) P = V ÷ I (d) P = I ÷ V
  9. 9.What does a capacitor do? (a) stores a little charge (b) turns a fan or wheels (c) is a resistance knob (d) blows if current is high
  10. 10.💡 What does LED stand for? (a) low energy device (b) light energy dial (c) light-emitting diode (d) large electric dial
  11. 11.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 99 Ω resistor? (a) white-white-brown (b) white-black-black (c) brown-white-black (d) white-white-black
  12. 12.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 0 % (c) 25 % (d) 5 %
  13. 13.⚡ A device works on 1.5 V and takes 0.2 A. What is its power (in watts)? =
  14. 14.⚡ A 36 W device works on 24 V. What current does it take (in amperes)? =
  15. 15.🔺 A current of 2.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  16. 16.🌈 In the resistor colour code, which number does brown stand for?
  17. 17.⚡ A device works on 6 V and takes 1 A. What is its power (in watts)? =
  18. 18.True or false: the flow of charge is measured in ohms (Ω). (a) False (b) True
  19. 19.⚡ A 0.375 W device works on 1.5 V. What current does it take (in amperes)? =
  20. 20.Which of these is measured in volts (V)? (a) the flow of charge (b) current (c) energy used each second (d) the push of a cell
  21. 21.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
  22. 22.Which of these saves electricity? (a) use LED lamps (b) use old filament bulbs (c) leave fridge door open (d) leave the TV on standby
  23. 23.🔍 Which is the odd one out? (a) use old filament bulbs (b) switch off empty rooms (c) run fans in empty rooms (d) leave the TV on standby
  24. 24.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) smaller (c) bigger (d) stay the same
  25. 25.🔺 A current of 20 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  26. 26.🌈 In the resistor colour code, which number does yellow stand for?
  27. 27.🌈 Which band is read first on a resistor? (a) the gold band (b) the widest gap (c) the one nearest an end (d) any band
  28. 28.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  29. 29.🔺 A 3.75 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  30. 30.📏 How many kilowatts (kW) is 4300 W? =
  31. 31.🧮 Resistors of 150 Ω, 68 Ω, 50 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
  32. 32.True or false: on an LED, the round-side leg is the cathode (−). (a) False (b) True
  33. 33.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 3.5 V supply. What current flows (in mA)?
  34. 34.🧾 A 100 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  35. 35.📏 Which unit measures the flow of charge? (a) volt (V) (b) ohm (Ω) (c) ampere (A) (d) watt (W)
  36. 36.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  37. 37.⚡ A 2.4 W device works on 24 V. What current does it take (in amperes)? =
  38. 38.Which of these saves electricity? (a) leave fridge door open (b) run fans in empty rooms (c) set the AC to 24 °C (d) leave the TV on standby
  39. 39.💡 An LED is joined to a 12 V battery with no resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) lights up (b) does not light (c) may burn out
  40. 40.🧮 Resistors of 330 Ω, 220 Ω and 470 Ω are joined in series. What is the total resistance (in ohms)?

Answer key

  1. ampere (A)
  2. capacitor
  3. voltmeter
  4. lights up
  5. 290
  6. False
  7. energy used each second
  8. P = V × I
  9. stores a little charge
  10. light-emitting diode
  11. white-white-black
  12. 5 %
  13. 0.3
  14. 1.5
  15. 5
  16. 1
  17. 6
  18. False
  19. 0.25
  20. the push of a cell
  21. 345
  22. use LED lamps
  23. switch off empty rooms
  24. bigger
  25. 8
  26. 4
  27. the one nearest an end
  28. 1
  29. 25
  30. 4.3
  31. 488
  32. False
  33. 5
  34. 0.2
  35. ampere (A)
  36. anode (+)
  37. 0.1
  38. set the AC to 24 °C
  39. may burn out
  40. 1020

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