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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 154 · 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.💡 An LED is joined to a 9 V battery through a 470 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) lights up (c) may burn out
  2. 2.True or false: a motor limits the current. (a) True (b) False
  3. 3.What does a resistor do? (a) has coloured bands (b) is a resistance knob (c) glows using little power (d) senses how bright it is
  4. 4.🧮 A 1.6 V battery is joined to 6 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
  5. 5.🔺 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
  6. 6.🔺 A current of 0.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  7. 7.🔺 A current of 20 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.🔺 A current of 40 mA flows when 4.8 V is joined across a resistor. What is its resistance (in ohms)?
  9. 9.Which of these wastes electricity? (a) close the fridge quickly (b) leave the TV on standby (c) switch off empty rooms (d) use LED lamps
  10. 10.True or false: a transistor boosts a small signal. (a) False (b) True
  11. 11.True or false: to run fans in empty rooms wastes electricity. (a) False (b) True
  12. 12.🔺 A current of 0.5 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  13. 13.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
  14. 14.⚡ A 27 W device works on 9 V. What current does it take (in amperes)? =
  15. 15.⚡ A device works on 12 V and takes 0.1 A. What is its power (in watts)? =
  16. 16.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
  17. 17.🔺 A current of 40 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.🔺 A current of 2 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  19. 19.True or false: on an LED, the longer leg is the anode (+). (a) False (b) True
  20. 20.🔺 A current of 0.25 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  21. 21.🧾 A family uses 190 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
  22. 22.🧮 Five equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  23. 23.🧩 A capacitor in a circuit can … (a) make light (b) store charge briefly (c) measure heat (d) spin a wheel
  24. 24.🔍 Which is the odd one out? (a) close the fridge quickly (b) use daylight to read (c) leave the TV on standby (d) unplug idle chargers
  25. 25.⚡ A device works on 24 V and takes 0.25 A. What is its power (in watts)? =
  26. 26.🔺 A current of 2.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  27. 27.🔺 A current of 1 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  28. 28.Which of these is measured in volts (V)? (a) energy used each second (b) current (c) the push of a cell (d) resistance
  29. 29.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  30. 30.🔺 A current of 50 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  31. 31.True or false: a resistor limits the current. (a) False (b) True
  32. 32.📏 In the water-pipe picture of a circuit, voltage is like … (a) the tap handle (b) the pipe colour (c) the water tank lid (d) the water pressure
  33. 33.🌈 A resistor has the colour bands blue, white, red. What is its value (in ohms)?
  34. 34.🔺 A current of 10 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a resistor (c) a capacitor (d) a diode
  36. 36.⚡ A 36 W device works on 12 V. What current does it take (in amperes)? =
  37. 37.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a filament bulb (c) a candle (d) an LED lamp
  38. 38.📏 How many amperes (A) is 1430 mA? =
  39. 39.🔺 A current of 25 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.🌈 A resistor has the colour bands brown, blue, orange. What is its value in kilo-ohms (kΩ)? =

Answer key

  1. lights up
  2. False
  3. has coloured bands
  4. 0.1
  5. I = V ÷ R
  6. 2
  7. 8
  8. 120
  9. leave the TV on standby
  10. True
  11. True
  12. 4
  13. ammeter
  14. 3
  15. 1.2
  16. False
  17. 6
  18. 5
  19. True
  20. 1
  21. 1520
  22. 20
  23. store charge briefly
  24. leave the TV on standby
  25. 6
  26. 30
  27. 5
  28. the push of a cell
  29. 230
  30. 11
  31. True
  32. the water pressure
  33. 6900
  34. 4.7
  35. a buzzer
  36. 3
  37. an LED lamp
  38. 1.43
  39. 3
  40. 16

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