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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 544 · 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.

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  1. 1.🧮 Two resistors in parallel give a total that is … (a) always zero (b) more than either one (c) their sum (d) less than either one
  2. 2.💡 A red LED uses 2 V and should get 25 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
  3. 3.True or false: the voltmeter is joined in series. (a) True (b) False
  4. 4.⚡ A device works on 24 V and takes 0.5 A. What is its power (in watts)? =
  5. 5.📏 How many amperes (A) is 2490 mA? =
  6. 6.🔺 A 2.4 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  7. 7.⚡ A 0.15 W device works on 1.5 V. What current does it take (in amperes)? =
  8. 8.🧩 Which component is a resistance knob? (a) resistor (b) diode (c) LED (d) potentiometer
  9. 9.⚡ Which formula gives electric power? (a) P = V × I (b) P = V + I (c) P = V ÷ I (d) P = I ÷ V
  10. 10.🔺 A 4.8 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  11. 11.🔺 A current of 20 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  12. 12.🌈 A resistor has the colour bands green, yellow, yellow. What is its value in kilo-ohms (kΩ)? =
  13. 13.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 160 Ω resistor? (a) brown-blue-red (b) brown-blue-black (c) brown-blue-brown (d) blue-brown-brown
  14. 14.⚡ A 36 W device works on 12 V. What current does it take (in amperes)? =
  15. 15.True or false: on an LED, the round-side leg is the anode (+). (a) False (b) True
  16. 16.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1000 (b) 10 (c) 100 (d) 1024
  17. 17.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
  18. 18.Which of these is measured in amperes (A)? (a) energy used each second (b) resistance (c) current (d) voltage
  19. 19.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  20. 20.🧾 A 50 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  21. 21.🔺 A current of 40 mA flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
  22. 22.🔺 A current of 0.25 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.🔍 Which is the odd one out? (a) use daylight to read (b) leave the TV on standby (c) close the fridge quickly (d) unplug idle chargers
  24. 24.🧾 A family uses 40 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
  25. 25.🔺 A 1.2 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  26. 26.📏 How many milliamperes (mA) is 1.68 A?
  27. 27.Which of these is measured in amperes (A)? (a) energy used each second (b) resistance (c) power (d) the flow of charge
  28. 28.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) stay the same (c) zero (d) smaller
  29. 29.🧮 Resistors of 68 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
  30. 30.True or false: to run fans in empty rooms saves electricity. (a) False (b) True
  31. 31.🧩 A capacitor in a circuit can … (a) make light (b) measure heat (c) spin a wheel (d) store charge briefly
  32. 32.True or false: to leave the TV on standby wastes electricity. (a) False (b) True
  33. 33.🧮 A 7.5 V battery is joined to 3 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  34. 34.True or false: the ammeter measures voltage. (a) False (b) True
  35. 35.🧾 A family uses 60 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  36. 36.🧮 Five equal 125 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  37. 37.🔺 A current of 0.1 A flows when 0.2 V is joined across a resistor. What is its resistance (in ohms)?
  38. 38.⚡ Power tells us … (a) the colour of light (b) energy used each second (c) the length of a wire (d) the size of a cell
  39. 39.⚡ A 9 W device works on 6 V. What current does it take (in amperes)? =
  40. 40.True or false: a motor beeps for an alarm. (a) False (b) True

Answer key

  1. less than either one
  2. 160
  3. False
  4. 12
  5. 2.49
  6. 20
  7. 0.1
  8. potentiometer
  9. P = V × I
  10. 40
  11. 6
  12. 540
  13. brown-blue-brown
  14. 3
  15. True
  16. 1000
  17. 920
  18. current
  19. 100
  20. 0.5
  21. 300
  22. 8
  23. leave the TV on standby
  24. 200
  25. 10
  26. 1680
  27. the flow of charge
  28. bigger
  29. 101
  30. False
  31. store charge briefly
  32. True
  33. 0.5
  34. False
  35. 240
  36. 25
  37. 2
  38. energy used each second
  39. 1.5
  40. False

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