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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 276 · 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.

NameDateTime takenScore ___ / 40
  1. 1.True or false: the ammeter measures current. (a) False (b) True
  2. 2.🔺 A current of 1.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.📏 How many amperes (A) is 2700 mA? =
  4. 4.What does a fuse do? (a) blows if current is high (b) stores a little charge (c) glows using little power (d) beeps for an alarm
  5. 5.🔺 A current of 40 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  6. 6.⚡ Which formula gives electric power? (a) P = V + I (b) P = I ÷ V (c) P = V × I (d) P = V ÷ I
  7. 7.💡 What happens if an LED is put in backwards? (a) it makes a sound (b) it changes colour (c) it does not light (d) it lights brighter
  8. 8.🔺 A 2 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  9. 9.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
  10. 10.🔺 A 6 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  11. 11.True or false: how much a part resists is measured in ohms (Ω). (a) False (b) True
  12. 12.🔺 A current of 1 A flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  13. 13.🌈 A resistor has the colour bands yellow, brown, yellow. What is its value in kilo-ohms (kΩ)? =
  14. 14.💡 An LED is joined to a 3 V battery through a 330 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
  15. 15.🔺 A current of 40 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  16. 16.🔺 A current of 1 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  17. 17.🔍 Which is the odd one out? (a) use LED lamps (b) iron one shirt at a time (c) unplug idle chargers (d) switch off empty rooms
  18. 18.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = I ÷ V (c) R = V ÷ I (d) R = V + I
  19. 19.⚡ A 0.5 W device works on 5 V. What current does it take (in amperes)? =
  20. 20.📏 Which unit measures voltage? (a) ampere (A) (b) watt (W) (c) ohm (Ω) (d) volt (V)
  21. 21.True or false: to run fans in empty rooms saves electricity. (a) False (b) True
  22. 22.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
  23. 23.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the gold band (c) any band (d) the widest gap
  24. 24.🌈 A resistor has the colour bands grey, brown, red. What is its value in kilo-ohms (kΩ)? =
  25. 25.Which of these is measured in watts (W)? (a) voltage (b) the push of a cell (c) the flow of charge (d) power
  26. 26.📏 How many milliamperes (mA) is 1.9 A?
  27. 27.True or false: the flow of charge is measured in ohms (Ω). (a) False (b) True
  28. 28.⚡ A device works on 3 V and takes 0.2 A. What is its power (in watts)? =
  29. 29.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
  30. 30.True or false: to use daylight to read wastes electricity. (a) False (b) True
  31. 31.🔺 A current of 0.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  32. 32.🔺 A current of 1.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.🔺 A current of 3 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.What does a motor do? (a) limits the current (b) blows if current is high (c) has coloured bands (d) turns a fan or wheels
  35. 35.🧩 Which part changes electrical energy into movement? (a) a motor (b) a fuse (c) a resistor (d) an LED
  36. 36.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
  37. 37.🔺 A current of 10 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) stays the same (c) gets smaller (d) gets bigger
  39. 39.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) a candle (c) an LED lamp (d) an oil lamp
  40. 40.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a resistor (c) a buzzer (d) a diode

Answer key

  1. True
  2. 15
  3. 2.7
  4. blows if current is high
  5. 6
  6. P = V × I
  7. it does not light
  8. 20
  9. wastes electricity
  10. 3
  11. True
  12. 8
  13. 410
  14. lights up
  15. 4
  16. 3
  17. iron one shirt at a time
  18. R = V ÷ I
  19. 0.1
  20. volt (V)
  21. False
  22. 460
  23. the one nearest an end
  24. 8.1
  25. power
  26. 1900
  27. False
  28. 0.6
  29. 345
  30. False
  31. 7.5
  32. 22.5
  33. 24
  34. turns a fan or wheels
  35. a motor
  36. voltmeter
  37. 2
  38. gets smaller
  39. an LED lamp
  40. a buzzer

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