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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 532 · 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.Which of these wastes electricity? (a) switch off empty rooms (b) use LED lamps (c) iron one shirt at a time (d) use daylight to read
  2. 2.🌈 In the resistor colour code, which number does violet stand for?
  3. 3.💡 An LED is joined to a 9 V battery with no 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
  4. 4.True or false: the ammeter measures voltage. (a) False (b) True
  5. 5.🌈 A resistor has the colour bands white, brown, red. What is its value in kilo-ohms (kΩ)? =
  6. 6.🧮 A 4 V battery is joined to 6 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
  7. 7.True or false: the voltmeter is joined in series. (a) False (b) True
  8. 8.Which of these wastes electricity? (a) close the fridge quickly (b) switch off empty rooms (c) leave the TV on standby (d) use LED lamps
  9. 9.📏 Which unit measures energy used each second? (a) volt (V) (b) ampere (A) (c) watt (W) (d) ohm (Ω)
  10. 10.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) close the fridge quickly (c) leave the TV on standby (d) switch off empty rooms
  11. 11.🔺 A current of 1.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  12. 12.🔺 A 5.5 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  13. 13.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V × I (c) R = V + I (d) R = V ÷ I
  14. 14.🔺 A current of 25 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
  15. 15.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 ampere (c) 1 kilowatt-hour (kWh) (d) 1 watt
  16. 16.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a motor (c) an LED (d) a resistor
  17. 17.🌈 Which band is read first on a resistor? (a) any band (b) the one nearest an end (c) the gold band (d) the widest gap
  18. 18.⚡ A 1 W device works on 5 V. What current does it take (in amperes)? =
  19. 19.🔺 A current of 0.25 A flows when 0.5 V is joined across a resistor. What is its resistance (in ohms)?
  20. 20.💡 What does LED stand for? (a) light energy dial (b) large electric dial (c) light-emitting diode (d) low energy device
  21. 21.⚡ Power tells us … (a) the size of a cell (b) the colour of light (c) the length of a wire (d) energy used each second
  22. 22.📏 How many watts (W) is 2.3 kW?
  23. 23.🔺 A current of 25 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  24. 24.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 2.5 V supply. What current flows (in mA)?
  25. 25.📏 How many milliamperes (mA) is 1.45 A?
  26. 26.🧾 A 1500 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
  27. 27.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
  28. 28.🧩 Which component glows using little power? (a) resistor (b) LED (c) buzzer (d) thermistor
  29. 29.🔺 A current of 40 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.📏 In the water-pipe picture of a circuit, resistance is like … (a) a narrow pipe (b) the flow of water (c) a bigger tank (d) the water pressure
  31. 31.🔺 A current of 25 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  32. 32.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
  33. 33.🔺 A 10 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  34. 34.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  35. 35.🌈 In the resistor colour code, which number does orange stand for?
  36. 36.🧾 A family uses 190 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  37. 37.🔺 A 3 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  38. 38.📏 How many kilowatts (kW) is 2700 W? =
  39. 39.🔺 A current of 0.25 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.🔺 A current of 1 A flows when 4 V is joined across a resistor. What is its resistance (in ohms)?

Answer key

  1. iron one shirt at a time
  2. 7
  3. may burn out
  4. False
  5. 9.1
  6. 0.25
  7. False
  8. leave the TV on standby
  9. watt (W)
  10. leave the TV on standby
  11. 22.5
  12. 25
  13. R = V ÷ I
  14. 12.5
  15. 1 kilowatt-hour (kWh)
  16. a motor
  17. the one nearest an end
  18. 0.2
  19. 2
  20. light-emitting diode
  21. energy used each second
  22. 2300
  23. 5
  24. 5
  25. 1450
  26. 7.5
  27. saves electricity
  28. LED
  29. 200
  30. a narrow pipe
  31. 5.5
  32. False
  33. 40
  34. cathode (−)
  35. 3
  36. 1710
  37. 0.25
  38. 2.7
  39. 0.5
  40. 4

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