← 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 476 · 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: to use old filament bulbs saves electricity. (a) False (b) True
  2. 2.🧾 A family uses 20 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
  3. 3.📏 How many watts (W) is 4.6 kW?
  4. 4.⚡ A 1 W device works on 5 V. What current does it take (in amperes)? =
  5. 5.⚡ A device works on 24 V and takes 0.1 A. What is its power (in watts)? =
  6. 6.⚡ A 1.5 W device works on 1.5 V. What current does it take (in amperes)? =
  7. 7.🔺 A current of 0.2 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  9. 9.True or false: the ammeter is joined across a part. (a) True (b) False
  10. 10.📏 How many milliamperes (mA) is 2.93 A?
  11. 11.🧮 A 1.75 V battery is joined to 4 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
  12. 12.💡 Why does an LED need a resistor in series? (a) to limit the current (b) to change its colour (c) to store charge (d) to make it brighter
  13. 13.🔺 A 7.5 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  14. 14.True or false: to leave the TV on standby wastes electricity. (a) False (b) True
  15. 15.🧮 Resistors of 330 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
  16. 16.🧮 Resistors of 330 Ω, 33 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
  17. 17.🔺 A 0.75 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  18. 18.🌈 In the resistor colour code, which number does yellow stand for?
  19. 19.🌈 A resistor has the colour bands yellow, orange, brown. What is its value (in ohms)?
  20. 20.📏 How many watts (W) is 2.1 kW?
  21. 21.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
  22. 22.Which of these wastes electricity? (a) iron one shirt at a time (b) use daylight to read (c) close the fridge quickly (d) set the AC to 24 °C
  23. 23.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
  24. 24.📏 Which unit measures power? (a) watt (W) (b) volt (V) (c) ampere (A) (d) ohm (Ω)
  25. 25.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 10 (b) 1024 (c) 100 (d) 1000
  26. 26.🔺 A 2 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  27. 27.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets bigger (c) gets smaller (d) becomes zero
  28. 28.🔺 A current of 0.2 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  29. 29.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 watt (c) 1 ampere (d) 1 kilowatt-hour (kWh)
  30. 30.🧮 A 14 V battery is joined to 4 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
  31. 31.💡 What happens if an LED is put in backwards? (a) it does not light (b) it lights brighter (c) it changes colour (d) it makes a sound
  32. 32.⚡ Which formula gives electric power? (a) P = V + I (b) P = V × I (c) P = V ÷ I (d) P = I ÷ V
  33. 33.⚡ Power tells us … (a) the length of a wire (b) the size of a cell (c) energy used each second (d) the colour of light
  34. 34.🧮 A 50 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  35. 35.🔺 A 0.4 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  36. 36.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
  37. 37.🔺 A 2 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  38. 38.🧩 Which component boosts a small signal? (a) buzzer (b) thermistor (c) capacitor (d) transistor
  39. 39.⚡ A 0.6 W device works on 3 V. What current does it take (in amperes)? =
  40. 40.⚡ A device works on 24 V and takes 0.2 A. What is its power (in watts)? =

Answer key

  1. False
  2. 140
  3. 4600
  4. 0.2
  5. 2.4
  6. 1
  7. 15
  8. 165
  9. False
  10. 2930
  11. 0.25
  12. to limit the current
  13. 2.5
  14. True
  15. 380
  16. 373
  17. 0.25
  18. 4
  19. 430
  20. 2100
  21. voltmeter
  22. iron one shirt at a time
  23. saves electricity
  24. watt (W)
  25. 1000
  26. 1
  27. gets smaller
  28. 1
  29. 1 kilowatt-hour (kWh)
  30. 1
  31. it does not light
  32. P = V × I
  33. energy used each second
  34. 160
  35. 0.1
  36. saves electricity
  37. 20
  38. transistor
  39. 0.2
  40. 4.8

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