← 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 916 · 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 blue, violet, orange. What is its value in kilo-ohms (kΩ)? =
  2. 2.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 6 V supply. What current flows (in mA)?
  3. 3.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
  4. 4.🔺 A current of 25 mA flows when 3.75 V is joined across a resistor. What is its resistance (in ohms)?
  5. 5.True or false: a motor glows using little power. (a) True (b) False
  6. 6.🌈 A resistor has the colour bands white, red, red. What is its value (in ohms)?
  7. 7.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 0 % (c) 50 % (d) 5 %
  8. 8.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
  9. 9.🔺 A current of 50 mA flows when 23.5 V is joined across a resistor. What is its resistance (in ohms)?
  10. 10.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V ÷ I (d) P = V × I
  11. 11.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
  12. 12.🔺 In the V-I-R triangle, how do we find I? (a) I = V + R (b) I = V ÷ R (c) I = V × R (d) I = R ÷ V
  13. 13.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to limit the current (c) to store charge (d) to make it brighter
  14. 14.⚡ A device works on 9 V and takes 0.2 A. What is its power (in watts)? =
  15. 15.🧮 Resistors of 220 Ω, 150 Ω, 470 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
  16. 16.🔺 A current of 0.2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  17. 17.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) bigger (c) stay the same (d) smaller
  18. 18.🧮 Two resistors in parallel give a total that is … (a) their sum (b) less than either one (c) always zero (d) more than either one
  19. 19.🌈 In the resistor colour code, which number does red stand for?
  20. 20.🔺 A 1.2 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  21. 21.What does a potentiometer do? (a) boosts a small signal (b) stores a little charge (c) is a resistance knob (d) makes a beeping sound
  22. 22.🌈 A resistor has the colour bands white, orange, yellow. What is its value in kilo-ohms (kΩ)? =
  23. 23.True or false: to leave the TV on standby saves electricity. (a) False (b) True
  24. 24.True or false: a capacitor turns a fan or wheels. (a) False (b) True
  25. 25.🔺 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
  26. 26.🔺 A current of 40 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  27. 27.⚡ A 2.4 W device works on 12 V. What current does it take (in amperes)? =
  28. 28.🔺 A current of 40 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  29. 29.🌈 A resistor has the colour bands brown, yellow, brown. What is its value (in ohms)?
  30. 30.📏 Which unit measures power? (a) ohm (Ω) (b) ampere (A) (c) watt (W) (d) volt (V)
  31. 31.🧮 A 14 V battery is joined to 8 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
  32. 32.🧮 Resistors of 22 Ω, 330 Ω, 47 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
  33. 33.🧮 Five equal 50 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  34. 34.Which of these is measured in volts (V)? (a) the flow of charge (b) how much a part resists (c) current (d) voltage
  35. 35.🧩 A capacitor in a circuit can … (a) measure heat (b) store charge briefly (c) spin a wheel (d) make light
  36. 36.🧮 Resistors of 50 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
  37. 37.🧾 A family uses 170 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
  38. 38.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
  39. 39.Which of these is measured in ohms (Ω)? (a) power (b) current (c) how much a part resists (d) energy used each second
  40. 40.Which of these saves electricity? (a) leave the TV on standby (b) use LED lamps (c) leave fridge door open (d) iron one shirt at a time

Answer key

  1. 67
  2. 20
  3. False
  4. 150
  5. False
  6. 9200
  7. 5 %
  8. False
  9. 470
  10. P = V × I
  11. wastes electricity
  12. I = V ÷ R
  13. to limit the current
  14. 1.8
  15. 860
  16. 0.8
  17. bigger
  18. less than either one
  19. 2
  20. 0.2
  21. is a resistance knob
  22. 930
  23. False
  24. False
  25. R = V ÷ I
  26. 200
  27. 0.2
  28. 8
  29. 140
  30. watt (W)
  31. 1
  32. 432
  33. 10
  34. voltage
  35. store charge briefly
  36. 100
  37. 1020
  38. 115
  39. how much a part resists
  40. use LED lamps

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