← 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 438 · 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: on an LED, the round-side leg is the cathode (−). (a) False (b) True
  2. 2.💡 What happens if an LED is put in backwards? (a) it makes a sound (b) it lights brighter (c) it does not light (d) it changes colour
  3. 3.🧮 Resistors of 220 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
  4. 4.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  5. 5.🔍 Which is the odd one out? (a) use LED lamps (b) iron one shirt at a time (c) run fans in empty rooms (d) use old filament bulbs
  6. 6.💡 What does LED stand for? (a) low energy device (b) large electric dial (c) light-emitting diode (d) light energy dial
  7. 7.🔺 A 2.5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  8. 8.🔺 A current of 1.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  9. 9.🧮 Resistors of 20 Ω, 10 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
  10. 10.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 kilowatt-hour (kWh) (c) 1 ampere (d) 1 volt
  11. 11.True or false: the push of a cell is measured in ohms (Ω). (a) True (b) False
  12. 12.💡 An LED is joined to a 12 V battery with no resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) may burn out (c) lights up
  13. 13.What does a buzzer do? (a) boosts a small signal (b) smooths a wobbly supply (c) senses how bright it is (d) makes a beeping sound
  14. 14.🧩 Which part changes electrical energy into sound? (a) a diode (b) a resistor (c) a capacitor (d) a buzzer
  15. 15.True or false: to unplug idle chargers wastes electricity. (a) True (b) False
  16. 16.🧾 A family uses 150 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
  17. 17.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) bigger (c) stay the same (d) zero
  18. 18.True or false: the ammeter is joined across a part. (a) False (b) True
  19. 19.🧮 Resistors of 33 Ω, 22 Ω, 22 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
  20. 20.🔺 A current of 0.1 A flows when 0.8 V is joined across a resistor. What is its resistance (in ohms)?
  21. 21.True or false: on an LED, the shorter leg is the anode (+). (a) False (b) True
  22. 22.🔺 A current of 1 A flows when 15 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V + I (c) P = V × I (d) P = I ÷ V
  24. 24.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets bigger (c) becomes zero (d) gets smaller
  25. 25.🧩 Which component lets current go one way? (a) diode (b) thermistor (c) capacitor (d) transistor
  26. 26.⚡ A device works on 12 V and takes 1.5 A. What is its power (in watts)? =
  27. 27.⚡ Power tells us … (a) the length of a wire (b) the colour of light (c) energy used each second (d) the size of a cell
  28. 28.🔺 A current of 0.1 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  29. 29.🌈 Which band is read first on a resistor? (a) any band (b) the gold band (c) the one nearest an end (d) the widest gap
  30. 30.Which of these wastes electricity? (a) run fans in empty rooms (b) unplug idle chargers (c) set the AC to 24 °C (d) switch off empty rooms
  31. 31.📏 Which unit measures how much a part resists? (a) watt (W) (b) ampere (A) (c) volt (V) (d) ohm (Ω)
  32. 32.🧩 Which component smooths a wobbly supply? (a) transistor (b) fuse (c) buzzer (d) capacitor
  33. 33.🧩 A capacitor in a circuit can … (a) measure heat (b) store charge briefly (c) spin a wheel (d) make light
  34. 34.True or false: to run fans in empty rooms wastes electricity. (a) False (b) True
  35. 35.🔺 A 0.2 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  36. 36.True or false: to iron one shirt at a time wastes electricity. (a) False (b) True
  37. 37.Which of these is measured in volts (V)? (a) voltage (b) energy used each second (c) the flow of charge (d) current
  38. 38.🔍 Which is the odd one out? (a) switch off empty rooms (b) iron one shirt at a time (c) run fans in empty rooms (d) leave the TV on standby
  39. 39.🌈 A resistor has the colour bands red, white, orange. What is its value (in ohms)?
  40. 40.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I × R (c) V = I ÷ R (d) V = I + R

Answer key

  1. False
  2. it does not light
  3. 253
  4. anode (+)
  5. use LED lamps
  6. light-emitting diode
  7. 10
  8. 6
  9. 250
  10. 1 kilowatt-hour (kWh)
  11. False
  12. may burn out
  13. makes a beeping sound
  14. a buzzer
  15. False
  16. 750
  17. bigger
  18. False
  19. 177
  20. 8
  21. False
  22. 15
  23. P = V × I
  24. gets smaller
  25. diode
  26. 18
  27. energy used each second
  28. 0.6
  29. the one nearest an end
  30. run fans in empty rooms
  31. ohm (Ω)
  32. capacitor
  33. store charge briefly
  34. True
  35. 0.1
  36. True
  37. voltage
  38. switch off empty rooms
  39. 29000
  40. V = I × R

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