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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 868 · 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.🧾 Which lamp gives the same light for the least power? (a) a candle (b) an LED lamp (c) an oil lamp (d) a filament bulb
  2. 2.🧩 A capacitor in a circuit can … (a) spin a wheel (b) measure heat (c) store charge briefly (d) make light
  3. 3.True or false: voltage is measured in watts (W). (a) True (b) False
  4. 4.True or false: a diode lets current go one way. (a) True (b) False
  5. 5.Which of these wastes electricity? (a) unplug idle chargers (b) set the AC to 24 °C (c) run fans in empty rooms (d) switch off empty rooms
  6. 6.🔺 A 1 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  7. 7.True or false: a fuse blows if current is high. (a) False (b) True
  8. 8.⚡ A device works on 24 V and takes 1.5 A. What is its power (in watts)? =
  9. 9.True or false: on an LED, the leg by the flat edge is the anode (+). (a) True (b) False
  10. 10.What does a capacitor do? (a) has coloured bands (b) boosts a small signal (c) smooths a wobbly supply (d) makes things spin
  11. 11.🔍 Which is the odd one out? (a) leave fridge door open (b) use old filament bulbs (c) use daylight to read (d) leave the TV on standby
  12. 12.🧾 A family uses 100 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
  13. 13.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) zero (c) stay the same (d) smaller
  14. 14.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 360 Ω resistor? (a) blue-orange-brown (b) orange-blue-red (c) orange-blue-black (d) orange-blue-brown
  15. 15.🧮 A 4.5 V battery is joined to 5 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
  16. 16.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I × R (c) V = R ÷ I (d) V = I + R
  17. 17.What does a diode do? (a) smooths a wobbly supply (b) lets current go one way (c) makes things spin (d) senses how bright it is
  18. 18.🔺 A current of 0.1 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  19. 19.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
  20. 20.⚡ Power tells us … (a) energy used each second (b) the size of a cell (c) the colour of light (d) the length of a wire
  21. 21.💡 An LED is joined to a 3 V battery through a 470 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) lights up (b) does not light (c) may burn out
  22. 22.🔺 A current of 0.2 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  23. 23.⚡ A 10 W device works on 5 V. What current does it take (in amperes)? =
  24. 24.🔺 A current of 2 A flows when 40 V is joined across a resistor. What is its resistance (in ohms)?
  25. 25.🔺 A 5 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  26. 26.📏 How many kilo-ohms (kΩ) is 5400 Ω? =
  27. 27.🔺 A current of 40 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  28. 28.🔺 A current of 0.25 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  29. 29.🔺 A 1.2 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  30. 30.🔺 A current of 1.5 A flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
  31. 31.True or false: voltage is measured in ohms (Ω). (a) False (b) True
  32. 32.True or false: to unplug idle chargers saves electricity. (a) False (b) True
  33. 33.🧮 Two resistors in parallel give a total that is … (a) always zero (b) their sum (c) more than either one (d) less than either one
  34. 34.Which of these wastes electricity? (a) unplug idle chargers (b) use LED lamps (c) use daylight to read (d) leave fridge door open
  35. 35.🌈 A resistor has the colour bands brown, black, red. What is its value in kilo-ohms (kΩ)? =
  36. 36.🧮 An 11 V battery is joined to 10 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  37. 37.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  38. 38.🔺 A 2 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  39. 39.🧾 A family uses 160 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
  40. 40.🧮 Resistors of 50 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?

Answer key

  1. an LED lamp
  2. store charge briefly
  3. False
  4. True
  5. run fans in empty rooms
  6. 0.5
  7. True
  8. 36
  9. False
  10. smooths a wobbly supply
  11. use daylight to read
  12. 600
  13. bigger
  14. orange-blue-brown
  15. 0.5
  16. V = I × R
  17. lets current go one way
  18. 10
  19. ammeter
  20. energy used each second
  21. does not light
  22. 1.2
  23. 2
  24. 20
  25. 0.25
  26. 5.4
  27. 16
  28. 2.5
  29. 10
  30. 5
  31. False
  32. True
  33. less than either one
  34. leave fridge door open
  35. 1
  36. 0.5
  37. 230
  38. 0.5
  39. 800
  40. 150

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