← 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 442 · 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.🌈 A resistor has the colour bands brown, yellow, orange. What is its value in kilo-ohms (kΩ)? =
  2. 2.🧮 Resistors of 10 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
  3. 3.💡 Why does an LED need a resistor in series? (a) to store charge (b) to make it brighter (c) to limit the current (d) to change its colour
  4. 4.🧩 Which part changes electrical energy into movement? (a) a motor (b) a fuse (c) an LED (d) a resistor
  5. 5.Which of these wastes electricity? (a) unplug idle chargers (b) iron one shirt at a time (c) close the fridge quickly (d) use LED lamps
  6. 6.🔺 A current of 2.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  7. 7.🔺 A current of 20 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.True or false: to close the fridge quickly saves electricity. (a) True (b) False
  9. 9.🧮 A 330 Ω resistor is joined in series with two equal 470 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  10. 10.🔺 A current of 3 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  11. 11.🧮 Resistors of 220 Ω, 330 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
  12. 12.🔺 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
  13. 13.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
  14. 14.💡 An LED is joined to a 9 V battery through a 470 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
  15. 15.🧩 Which component smooths a wobbly supply? (a) thermistor (b) capacitor (c) diode (d) LED
  16. 16.🔺 A current of 3 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  17. 17.🔺 A current of 0.25 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.🔺 A current of 2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  19. 19.📏 How many ohms (Ω) is 5.7 kΩ?
  20. 20.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 5 V supply. What current flows (in mA)?
  21. 21.What does a buzzer do? (a) has coloured bands (b) limits the current (c) beeps for an alarm (d) blows if current is high
  22. 22.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 kilowatt-hour (kWh) (c) 1 ampere (d) 1 volt
  23. 23.🌈 Which band is read first on a resistor? (a) the gold band (b) the one nearest an end (c) the widest gap (d) any band
  24. 24.📏 Which unit measures how much a part resists? (a) ohm (Ω) (b) volt (V) (c) ampere (A) (d) watt (W)
  25. 25.🧩 Which component makes a beeping sound? (a) buzzer (b) LDR (c) resistor (d) diode
  26. 26.🌈 A resistor has the colour bands white, red, orange. What is its value (in ohms)?
  27. 27.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an LED lamp (c) a candle (d) an oil lamp
  28. 28.True or false: a thermistor senses how hot it is. (a) True (b) False
  29. 29.🔺 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
  30. 30.Which of these is measured in amperes (A)? (a) how much a part resists (b) energy used each second (c) the push of a cell (d) the flow of charge
  31. 31.🌈 A resistor has the colour bands white, orange, yellow. What is its value in kilo-ohms (kΩ)? =
  32. 32.🔍 Which is the odd one out? (a) iron one shirt at a time (b) leave the TV on standby (c) leave fridge door open (d) switch off empty rooms
  33. 33.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 4 V supply. What current flows (in mA)?
  34. 34.True or false: the push of a cell is measured in volts (V). (a) False (b) True
  35. 35.🔺 A current of 40 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  36. 36.💡 A red LED uses 2 V and should get 25 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
  37. 37.True or false: the ammeter is joined in series. (a) True (b) False
  38. 38.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
  39. 39.🔺 A current of 0.1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.True or false: energy used each second is measured in watts (W). (a) True (b) False

Answer key

  1. 14
  2. 30
  3. to limit the current
  4. a motor
  5. iron one shirt at a time
  6. 12.5
  7. 200
  8. True
  9. 565
  10. 12
  11. 600
  12. R = V ÷ I
  13. wastes electricity
  14. lights up
  15. capacitor
  16. 15
  17. 1.5
  18. 40
  19. 5700
  20. 10
  21. beeps for an alarm
  22. 1 kilowatt-hour (kWh)
  23. the one nearest an end
  24. ohm (Ω)
  25. buzzer
  26. 92000
  27. an LED lamp
  28. True
  29. gets smaller
  30. the flow of charge
  31. 930
  32. switch off empty rooms
  33. 20
  34. True
  35. 16
  36. 400
  37. True
  38. 567
  39. 1
  40. True

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