← 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 898 · 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.🧮 Four equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  2. 2.True or false: on an LED, the longer leg is the anode (+). (a) False (b) True
  3. 3.🔺 A current of 0.2 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  4. 4.True or false: a buzzer beeps for an alarm. (a) False (b) True
  5. 5.🔺 A current of 40 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  6. 6.🔺 A current of 40 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  7. 7.🔺 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
  8. 8.🔺 A current of 20 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  9. 9.⚡ Power tells us … (a) energy used each second (b) the size of a cell (c) the colour of light (d) the length of a wire
  10. 10.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) more than either one (c) their sum (d) always zero
  11. 11.🌈 In the resistor colour code, which number does grey stand for?
  12. 12.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 340 Ω resistor? (a) orange-yellow-black (b) orange-yellow-red (c) yellow-orange-brown (d) orange-yellow-brown
  13. 13.True or false: the voltmeter is joined across a part. (a) True (b) False
  14. 14.🔺 A current of 0.2 A flows when 1.6 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a resistor (c) a motor (d) an LED
  16. 16.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 2100 Ω resistor? (a) red-brown-orange (b) red-brown-brown (c) red-brown-red (d) brown-red-red
  17. 17.💡 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
  18. 18.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 1 hour. How many watt-hours (Wh) are saved?
  19. 19.⚡ A device works on 1.5 V and takes 0.5 A. What is its power (in watts)? =
  20. 20.📏 Which unit measures energy used each second? (a) ohm (Ω) (b) ampere (A) (c) volt (V) (d) watt (W)
  21. 21.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an LED lamp (c) an oil lamp (d) a candle
  22. 22.📏 In the water-pipe picture of a circuit, resistance is like … (a) a narrow pipe (b) the flow of water (c) a bigger tank (d) the water pressure
  23. 23.🔺 A current of 20 mA flows when 9.4 V is joined across a resistor. What is its resistance (in ohms)?
  24. 24.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  25. 25.🔺 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
  26. 26.True or false: the ammeter measures voltage. (a) True (b) False
  27. 27.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 6 hours. How many watt-hours (Wh) are saved?
  28. 28.🧮 A 47 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)?
  29. 29.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it changes colour (c) it does not light (d) it makes a sound
  30. 30.📏 How many kilo-ohms (kΩ) is 3700 Ω? =
  31. 31.🧩 A capacitor in a circuit can … (a) store charge briefly (b) make light (c) measure heat (d) spin a wheel
  32. 32.📏 In the water-pipe picture of a circuit, current is like … (a) a narrow pipe (b) the flow of water (c) the water pressure (d) the pipe colour
  33. 33.🔺 A current of 40 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.🔺 A current of 0.25 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.🔺 A 5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  36. 36.🔺 A current of 2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.🧮 A 33 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)?
  38. 38.🧮 A 100 Ω resistor is joined in series with two equal 330 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  39. 39.Which of these is measured in volts (V)? (a) energy used each second (b) the flow of charge (c) how much a part resists (d) voltage
  40. 40.📏 Which unit measures current? (a) watt (W) (b) volt (V) (c) ampere (A) (d) ohm (Ω)

Answer key

  1. 10
  2. True
  3. 1
  4. True
  5. 250
  6. 16
  7. I = V ÷ R
  8. 2
  9. energy used each second
  10. less than either one
  11. 8
  12. orange-yellow-brown
  13. True
  14. 8
  15. a motor
  16. red-brown-red
  17. to limit the current
  18. 85
  19. 0.75
  20. watt (W)
  21. an LED lamp
  22. a narrow pipe
  23. 470
  24. 4
  25. V = I × R
  26. False
  27. 306
  28. 157
  29. it does not light
  30. 3.7
  31. store charge briefly
  32. the flow of water
  33. 12
  34. 1
  35. 20
  36. 20
  37. 143
  38. 265
  39. voltage
  40. ampere (A)

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