← 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 367 · 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 current of 2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  2. 2.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I + R (c) V = I × R (d) V = R ÷ I
  3. 3.🔍 Which is the odd one out? (a) unplug idle chargers (b) set the AC to 24 °C (c) switch off empty rooms (d) leave fridge door open
  4. 4.💡 An LED is joined to a 5 V battery through a 330 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) may burn out (b) does not light (c) lights up
  5. 5.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  6. 6.🔺 A current of 2.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  7. 7.🔺 A current of 25 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.⚡ An 18 W device works on 9 V. What current does it take (in amperes)? =
  9. 9.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
  10. 10.⚡ A device works on 6 V and takes 1 A. What is its power (in watts)? =
  11. 11.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) bigger (c) zero (d) stay the same
  12. 12.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  13. 13.🔺 A 2.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  14. 14.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to make it brighter (c) to store charge (d) to limit the current
  15. 15.🔺 A 4 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  16. 16.🧮 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
  17. 17.🧮 Two equal 470 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  18. 18.🧮 Three equal 30 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  19. 19.📏 How many milliamperes (mA) is 0.26 A?
  20. 20.⚡ Power tells us … (a) the length of a wire (b) energy used each second (c) the size of a cell (d) the colour of light
  21. 21.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 kilowatt-hour (kWh) (c) 1 volt (d) 1 watt
  22. 22.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1024 (b) 10 (c) 1000 (d) 100
  23. 23.True or false: a buzzer smooths a wobbly supply. (a) False (b) True
  24. 24.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
  25. 25.🧮 Four equal 400 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  26. 26.🧾 A family uses 90 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  27. 27.📏 How many ohms (Ω) is 6.8 kΩ?
  28. 28.🔺 A current of 1.5 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  29. 29.Which of these saves electricity? (a) unplug idle chargers (b) leave the TV on standby (c) iron one shirt at a time (d) run fans in empty rooms
  30. 30.True or false: a buzzer makes a beeping sound. (a) False (b) True
  31. 31.⚡ Which formula gives electric power? (a) P = V + I (b) P = V ÷ I (c) P = V × I (d) P = I ÷ V
  32. 32.True or false: to iron one shirt at a time saves electricity. (a) True (b) False
  33. 33.🔺 A current of 25 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.🔺 A current of 20 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  35. 35.🔺 A 30 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  36. 36.🔺 A 6 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  37. 37.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) becomes zero (c) gets bigger (d) stays the same
  38. 38.🧩 Which component limits the current? (a) LDR (b) buzzer (c) potentiometer (d) resistor
  39. 39.⚡ A device works on 1.5 V and takes 3 A. What is its power (in watts)? =
  40. 40.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter

Answer key

  1. 6
  2. V = I × R
  3. leave fridge door open
  4. does not light
  5. 20
  6. 7.5
  7. 10
  8. 2
  9. voltmeter
  10. 6
  11. bigger
  12. anode (+)
  13. 0.5
  14. to limit the current
  15. 40
  16. less than either one
  17. 235
  18. 10
  19. 260
  20. energy used each second
  21. 1 kilowatt-hour (kWh)
  22. 1000
  23. False
  24. saves electricity
  25. 100
  26. 810
  27. 6800
  28. 2
  29. unplug idle chargers
  30. True
  31. P = V × I
  32. False
  33. 3.75
  34. 250
  35. 3
  36. 50
  37. gets smaller
  38. resistor
  39. 4.5
  40. voltmeter

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