← 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 324 · 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 50 Ω resistor is joined in series with two equal 50 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  2. 2.True or false: a resistor blows if current is high. (a) False (b) True
  3. 3.📏 Which unit measures resistance? (a) ohm (Ω) (b) volt (V) (c) watt (W) (d) ampere (A)
  4. 4.🧮 Three equal 300 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  5. 5.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  6. 6.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 65 Ω resistor? (a) green-blue-black (b) blue-green-black (c) violet-green-black (d) blue-green-brown
  7. 7.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
  8. 8.🧩 Which component lets current go one way? (a) transistor (b) diode (c) potentiometer (d) motor
  9. 9.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V × I (c) P = I ÷ V (d) P = V + I
  10. 10.What does a thermistor do? (a) senses how hot it is (b) limits the current (c) blows if current is high (d) lets current go one way
  11. 11.🔺 A 3.75 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  12. 12.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 8 hours. How many watt-hours (Wh) are saved?
  13. 13.🔺 A 12 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  14. 14.💡 An LED is joined to a 9 V battery through a 220 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) may burn out (c) lights up
  15. 15.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 24000 Ω resistor? (a) red-yellow-yellow (b) yellow-red-orange (c) red-yellow-red (d) red-yellow-orange
  16. 16.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) bigger (c) zero (d) stay the same
  17. 17.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  18. 18.🧮 Resistors of 22 Ω, 20 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
  19. 19.🔺 A current of 0.1 A flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
  20. 20.🔺 A current of 1.5 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
  21. 21.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 3 V supply. What current flows (in mA)?
  22. 22.🔺 A current of 0.1 A flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.What does an LED do? (a) glows using little power (b) turns a fan or wheels (c) makes a beeping sound (d) limits the current
  24. 24.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
  25. 25.🧩 Which part changes electrical energy into movement? (a) a resistor (b) an LED (c) a fuse (d) a motor
  26. 26.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 0 % (c) 5 % (d) 50 %
  27. 27.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
  28. 28.True or false: power is measured in volts (V). (a) False (b) True
  29. 29.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 630 Ω resistor? (a) blue-orange-brown (b) blue-orange-red (c) blue-orange-black (d) orange-blue-brown
  30. 30.🧮 A 20 Ω resistor is joined in series with two equal 20 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  31. 31.🔺 A current of 50 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  32. 32.What does a motor do? (a) beeps for an alarm (b) stores a little charge (c) senses how bright it is (d) makes things spin
  33. 33.🧮 Four equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  34. 34.🔺 A current of 50 mA flows when 12.5 V is joined across a resistor. What is its resistance (in ohms)?
  35. 35.🔺 A current of 0.25 A flows when 3.75 V is joined across a resistor. What is its resistance (in ohms)?
  36. 36.Which of these is measured in volts (V)? (a) energy used each second (b) voltage (c) how much a part resists (d) the flow of charge
  37. 37.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = I × R (c) V = R ÷ I (d) V = I ÷ R
  38. 38.🔺 A current of 25 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  39. 39.🔺 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
  40. 40.⚡ A device works on 24 V and takes 0.2 A. What is its power (in watts)? =

Answer key

  1. 75
  2. False
  3. ohm (Ω)
  4. 100
  5. 500
  6. blue-green-black
  7. 2300
  8. diode
  9. P = V × I
  10. senses how hot it is
  11. 25
  12. 408
  13. 3
  14. lights up
  15. red-yellow-orange
  16. bigger
  17. anode (+)
  18. 92
  19. 12
  20. 8
  21. 5
  22. 15
  23. glows using little power
  24. 460
  25. a motor
  26. 5 %
  27. wastes electricity
  28. False
  29. blue-orange-brown
  30. 30
  31. 20
  32. makes things spin
  33. 25
  34. 250
  35. 15
  36. voltage
  37. V = I × R
  38. 8.25
  39. I = V ÷ R
  40. 4.8

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