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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 833 · 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.🧾 A family uses 160 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  2. 2.Which of these is measured in amperes (A)? (a) power (b) the flow of charge (c) the push of a cell (d) voltage
  3. 3.📏 How many kilowatts (kW) is 1150 W? =
  4. 4.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 50 % (c) 5 % (d) 0 %
  5. 5.🧩 A capacitor in a circuit can … (a) measure heat (b) store charge briefly (c) spin a wheel (d) make light
  6. 6.True or false: to run fans in empty rooms saves electricity. (a) False (b) True
  7. 7.🔍 Which is the odd one out? (a) run fans in empty rooms (b) use LED lamps (c) use old filament bulbs (d) leave fridge door open
  8. 8.🔺 A current of 20 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  9. 9.🧮 Resistors of 10 Ω, 33 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
  10. 10.🧮 Resistors of 150 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
  11. 11.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) stay the same (c) bigger (d) smaller
  12. 12.📏 How many kilowatts (kW) is 4450 W? =
  13. 13.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I ÷ R (c) V = I × R (d) V = I + R
  14. 14.🧮 A 2.4 V battery is joined to 12 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  15. 15.What does a motor do? (a) lets current go one way (b) smooths a wobbly supply (c) makes things spin (d) has coloured bands
  16. 16.🧾 A 50 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  17. 17.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = R ÷ V (c) I = V × R (d) I = V + R
  18. 18.🔺 A current of 0.1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  19. 19.🌈 In the resistor colour code, which number does yellow stand for?
  20. 20.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
  21. 21.True or false: a diode senses how hot it is. (a) True (b) False
  22. 22.🔺 A 20 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
  23. 23.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  24. 24.🌈 A resistor has the colour bands orange, violet, yellow. What is its value in kilo-ohms (kΩ)? =
  25. 25.🌈 In the resistor colour code, which number does red stand for?
  26. 26.🔺 A current of 40 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
  27. 27.📏 How many kilo-ohms (kΩ) is 3800 Ω? =
  28. 28.🧮 Resistors of 10 Ω, 22 Ω, 33 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
  29. 29.🌈 Which band is read first on a resistor? (a) any band (b) the widest gap (c) the gold band (d) the one nearest an end
  30. 30.Which of these is measured in volts (V)? (a) the flow of charge (b) power (c) the push of a cell (d) current
  31. 31.🧩 Which part changes electrical energy into movement? (a) a fuse (b) an LED (c) a resistor (d) a motor
  32. 32.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
  33. 33.🔺 A 6 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  34. 34.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  35. 35.🔺 A current of 2 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
  36. 36.🔺 A current of 1 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.📏 How many milliamperes (mA) make 1 ampere? (a) 100 (b) 60 (c) 1000 (d) 10
  38. 38.📏 How many amperes (A) is 2020 mA? =
  39. 39.💡 A red LED uses 2 V and should get 20 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
  40. 40.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?

Answer key

  1. 640
  2. the flow of charge
  3. 1.15
  4. 5 %
  5. store charge briefly
  6. False
  7. use LED lamps
  8. 400
  9. 143
  10. 250
  11. bigger
  12. 4.45
  13. V = I × R
  14. 0.1
  15. makes things spin
  16. 0.5
  17. I = V ÷ R
  18. 0.2
  19. 4
  20. False
  21. False
  22. 40
  23. cathode (−)
  24. 370
  25. 2
  26. 4.8
  27. 3.8
  28. 85
  29. the one nearest an end
  30. the push of a cell
  31. a motor
  32. saves electricity
  33. 40
  34. 10
  35. 6
  36. 6
  37. 1000
  38. 2.02
  39. 500
  40. 2300

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