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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 871 · 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 home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
  2. 2.🔺 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
  3. 3.🧾 Which lamp gives the same light for the least power? (a) a candle (b) a filament bulb (c) an oil lamp (d) an LED lamp
  4. 4.📏 How many kilo-ohms (kΩ) is 400 Ω? =
  5. 5.🔺 A 12 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  6. 6.What does a buzzer do? (a) blows if current is high (b) makes a beeping sound (c) senses how bright it is (d) stores a little charge
  7. 7.🧮 Four equal 80 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  8. 8.🔺 A 13.2 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  9. 9.🔺 A 0.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  10. 10.📏 Which unit measures energy used each second? (a) volt (V) (b) ampere (A) (c) watt (W) (d) ohm (Ω)
  11. 11.🔺 A current of 0.1 A flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
  12. 12.⚡ A device works on 3 V and takes 0.2 A. What is its power (in watts)? =
  13. 13.True or false: the ammeter measures voltage. (a) False (b) True
  14. 14.True or false: energy used each second is measured in ohms (Ω). (a) True (b) False
  15. 15.🔺 A 1 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  16. 16.🧩 A capacitor in a circuit can … (a) make light (b) store charge briefly (c) spin a wheel (d) measure heat
  17. 17.🔺 A current of 1.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.True or false: resistance is measured in ohms (Ω). (a) False (b) True
  19. 19.🧮 A 14 V battery is joined to 2 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  20. 20.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  21. 21.🔺 A 2 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  22. 22.🌈 A resistor has the colour bands brown, blue, black. What is its value (in ohms)?
  23. 23.🌈 Which band is read first on a resistor? (a) the widest gap (b) the gold band (c) any band (d) the one nearest an end
  24. 24.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a diode (c) a buzzer (d) a resistor
  25. 25.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) becomes zero (c) gets smaller (d) stays the same
  26. 26.💡 What does LED stand for? (a) large electric dial (b) low energy device (c) light energy dial (d) light-emitting diode
  27. 27.What does a capacitor do? (a) blows if current is high (b) is a resistance knob (c) stores a little charge (d) limits the current
  28. 28.🌈 A resistor has the colour bands grey, orange, black. What is its value (in ohms)?
  29. 29.🧮 A 12 V battery is joined to 12 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  30. 30.🌈 A resistor has the colour bands white, yellow, red. What is its value (in ohms)?
  31. 31.💡 What happens if an LED is put in backwards? (a) it does not light (b) it lights brighter (c) it changes colour (d) it makes a sound
  32. 32.⚡ A device works on 1.5 V and takes 1 A. What is its power (in watts)? =
  33. 33.⚡ A device works on 9 V and takes 1.5 A. What is its power (in watts)? =
  34. 34.🧾 A family uses 110 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
  35. 35.True or false: to unplug idle chargers saves electricity. (a) False (b) True
  36. 36.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 kilowatt-hour (kWh) (c) 1 ampere (d) 1 watt
  37. 37.🔺 A current of 50 mA flows when 23.5 V is joined across a resistor. What is its resistance (in ohms)?
  38. 38.🔺 A current of 40 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
  39. 39.🔺 A current of 50 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.⚡ A device works on 24 V and takes 1.5 A. What is its power (in watts)? =

Answer key

  1. 920
  2. V = I × R
  3. an LED lamp
  4. 0.4
  5. 3
  6. makes a beeping sound
  7. 20
  8. 40
  9. 0.1
  10. watt (W)
  11. 12
  12. 0.6
  13. False
  14. False
  15. 0.25
  16. store charge briefly
  17. 15
  18. True
  19. 1
  20. 20
  21. 10
  22. 16
  23. the one nearest an end
  24. a buzzer
  25. gets smaller
  26. light-emitting diode
  27. stores a little charge
  28. 83
  29. 0.5
  30. 9400
  31. it does not light
  32. 1.5
  33. 13.5
  34. 880
  35. True
  36. 1 kilowatt-hour (kWh)
  37. 470
  38. 20
  39. 10
  40. 36

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