← 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 896 · 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 red, brown, orange. What is its value (in ohms)?
  2. 2.⚡ A 9 W device works on 3 V. What current does it take (in amperes)? =
  3. 3.Which of these is measured in watts (W)? (a) current (b) the push of a cell (c) resistance (d) energy used each second
  4. 4.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
  5. 5.📏 How many milliamperes (mA) is 0.19 A?
  6. 6.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 32000 Ω resistor? (a) orange-red-red (b) red-orange-orange (c) orange-red-orange (d) orange-red-yellow
  7. 7.🔺 A current of 2.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.🧮 Resistors of 22 Ω, 50 Ω and 47 Ω are joined in series. What is the total resistance (in ohms)?
  9. 9.⚡ A 0.6 W device works on 3 V. What current does it take (in amperes)? =
  10. 10.Which of these wastes electricity? (a) close the fridge quickly (b) use old filament bulbs (c) set the AC to 24 °C (d) use LED lamps
  11. 11.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = V × I (c) R = V ÷ I (d) R = I ÷ V
  12. 12.True or false: voltage is measured in volts (V). (a) True (b) False
  13. 13.⚡ A device works on 9 V and takes 0.5 A. What is its power (in watts)? =
  14. 14.🌈 In the resistor colour code, which number does red stand for?
  15. 15.🧮 Five equal 25 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  16. 16.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
  17. 17.🔺 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
  18. 18.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
  19. 19.🌈 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
  20. 20.🧮 A 1.5 V battery is joined to 4 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
  21. 21.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 4 V supply. What current flows (in mA)?
  22. 22.🔺 A current of 0.25 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.🔺 An 8.8 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  24. 24.🌈 In the resistor colour code, which number does grey stand for?
  25. 25.🌈 A resistor has the colour bands green, red, black. What is its value (in ohms)?
  26. 26.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
  27. 27.📏 How many milliamperes (mA) is 2.56 A?
  28. 28.🧮 Resistors of 100 Ω, 47 Ω and 470 Ω are joined in series. What is the total resistance (in ohms)?
  29. 29.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 25 % (c) 0 % (d) 50 %
  30. 30.True or false: a potentiometer lets current go one way. (a) True (b) False
  31. 31.🔺 A current of 0.25 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  32. 32.⚡ An 18 W device works on 12 V. What current does it take (in amperes)? =
  33. 33.📏 How many kilowatts (kW) is 450 W? =
  34. 34.🔺 A current of 0.5 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  35. 35.⚡ Which formula gives electric power? (a) P = V × I (b) P = I ÷ V (c) P = V + I (d) P = V ÷ I
  36. 36.💡 A red LED uses 2 V and should get 25 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
  37. 37.🧩 Which component blows if current is high? (a) LED (b) fuse (c) transistor (d) motor
  38. 38.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
  39. 39.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 1 hour. How many watt-hours (Wh) are saved?
  40. 40.True or false: a motor makes things spin. (a) True (b) False

Answer key

  1. 21000
  2. 3
  3. energy used each second
  4. saves electricity
  5. 190
  6. orange-red-orange
  7. 25
  8. 119
  9. 0.2
  10. use old filament bulbs
  11. R = V ÷ I
  12. True
  13. 4.5
  14. 2
  15. 5
  16. 345
  17. I = V ÷ R
  18. 1150
  19. the one nearest an end
  20. 0.25
  21. 20
  22. 12
  23. 40
  24. 8
  25. 52
  26. False
  27. 2560
  28. 617
  29. 5 %
  30. False
  31. 3
  32. 1.5
  33. 0.45
  34. 10
  35. P = V × I
  36. 280
  37. fuse
  38. voltmeter
  39. 34
  40. True

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