← 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 152 · 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.🔺 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
  2. 2.🔺 A current of 10 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.🔺 A current of 40 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
  4. 4.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  5. 5.🔺 A 0.5 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  6. 6.⚡ A device works on 24 V and takes 0.2 A. What is its power (in watts)? =
  7. 7.🧩 Which part changes electrical energy into movement? (a) a motor (b) a resistor (c) an LED (d) a fuse
  8. 8.💡 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
  9. 9.🧾 A family uses 190 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  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.True or false: power is measured in volts (V). (a) False (b) True
  12. 12.⚡ Power tells us … (a) the length of a wire (b) the colour of light (c) energy used each second (d) the size of a cell
  13. 13.📏 Which unit measures voltage? (a) watt (W) (b) ampere (A) (c) volt (V) (d) ohm (Ω)
  14. 14.💡 A blue LED uses 3 V and should get 25 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
  15. 15.📏 How many amperes (A) is 2080 mA? =
  16. 16.🔺 A current of 50 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  17. 17.True or false: to use daylight to read wastes electricity. (a) True (b) False
  18. 18.⚡ A device works on 9 V and takes 0.1 A. What is its power (in watts)? =
  19. 19.🔍 Which is the odd one out? (a) use old filament bulbs (b) use daylight to read (c) switch off empty rooms (d) close the fridge quickly
  20. 20.True or false: a diode smooths a wobbly supply. (a) False (b) True
  21. 21.Which of these saves electricity? (a) leave fridge door open (b) use LED lamps (c) iron one shirt at a time (d) leave the TV on standby
  22. 22.🧾 One “unit” on an electricity bill is … (a) 1 kilowatt-hour (kWh) (b) 1 ampere (c) 1 watt (d) 1 volt
  23. 23.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 5 % (c) 25 % (d) 50 %
  24. 24.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
  25. 25.🌈 A resistor has the colour bands green, brown, red. What is its value in kilo-ohms (kΩ)? =
  26. 26.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a capacitor (c) a buzzer (d) a diode
  27. 27.🧮 Two resistors in parallel give a total that is … (a) always zero (b) less than either one (c) more than either one (d) their sum
  28. 28.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = R ÷ I (c) V = I × R (d) V = I ÷ R
  29. 29.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) zero (c) smaller (d) bigger
  30. 30.Which of these saves electricity? (a) leave the TV on standby (b) iron one shirt at a time (c) run fans in empty rooms (d) set the AC to 24 °C
  31. 31.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 89000 Ω resistor? (a) grey-white-yellow (b) grey-white-red (c) grey-white-orange (d) white-grey-orange
  32. 32.🌈 A resistor has the colour bands white, violet, orange. What is its value (in ohms)?
  33. 33.🔺 A current of 0.1 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.🌈 A resistor has the colour bands violet, orange, red. What is its value (in ohms)?
  35. 35.🧮 Resistors of 33 Ω, 330 Ω, 100 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
  36. 36.🧩 Which component senses how hot it is? (a) resistor (b) LED (c) buzzer (d) thermistor
  37. 37.🔺 A current of 50 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.🔺 A 4 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  39. 39.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.🔺 A current of 10 mA flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?

Answer key

  1. R = V ÷ I
  2. 1.2
  3. 4.8
  4. anode (+)
  5. 0.25
  6. 4.8
  7. a motor
  8. to limit the current
  9. 1710
  10. P = V × I
  11. False
  12. energy used each second
  13. volt (V)
  14. 240
  15. 2.08
  16. 10
  17. False
  18. 0.9
  19. use old filament bulbs
  20. False
  21. use LED lamps
  22. 1 kilowatt-hour (kWh)
  23. 5 %
  24. 115
  25. 5.1
  26. a buzzer
  27. less than either one
  28. V = I × R
  29. bigger
  30. set the AC to 24 °C
  31. grey-white-orange
  32. 97000
  33. 1.2
  34. 7300
  35. 496
  36. thermistor
  37. 25
  38. 20
  39. 4
  40. 150

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