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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 124 · 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: a diode beeps for an alarm. (a) False (b) True
  2. 2.🧩 Which part changes electrical energy into sound? (a) a diode (b) a capacitor (c) a resistor (d) a buzzer
  3. 3.🌈 A resistor has the colour bands brown, brown, black. What is its value (in ohms)?
  4. 4.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  5. 5.⚡ Power tells us … (a) the size of a cell (b) the length of a wire (c) energy used each second (d) the colour of light
  6. 6.🧮 Resistors of 50 Ω, 10 Ω, 33 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
  7. 7.📏 How many ohms (Ω) is 1 kΩ?
  8. 8.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) True (b) False
  9. 9.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  10. 10.🧾 A family uses 60 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
  11. 11.True or false: a capacitor is a resistance knob. (a) True (b) False
  12. 12.True or false: a potentiometer turns a fan or wheels. (a) True (b) False
  13. 13.🔺 A 9 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  14. 14.🔺 A current of 1.5 A flows when 30 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.🔺 A current of 0.25 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  16. 16.🌈 Which band is read first on a resistor? (a) any band (b) the gold band (c) the one nearest an end (d) the widest gap
  17. 17.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
  18. 18.📏 How many amperes (A) is 90 mA? =
  19. 19.🔺 A current of 1.5 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  20. 20.🧮 A 4.5 V battery is joined to 6 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  21. 21.🧾 A 200 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  22. 22.📏 In the water-pipe picture of a circuit, resistance is like … (a) the water pressure (b) the flow of water (c) a narrow pipe (d) a bigger tank
  23. 23.🔺 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
  24. 24.⚡ A 48 W device works on 24 V. What current does it take (in amperes)? =
  25. 25.🔺 A current of 10 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
  26. 26.🌈 A resistor has the colour bands violet, blue, black. What is its value (in ohms)?
  27. 27.True or false: a transistor stores a little charge. (a) False (b) True
  28. 28.Which of these saves electricity? (a) leave the TV on standby (b) set the AC to 24 °C (c) use old filament bulbs (d) leave fridge door open
  29. 29.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 volt (c) 1 ampere (d) 1 kilowatt-hour (kWh)
  30. 30.🔺 A current of 20 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  31. 31.🔺 A current of 0.5 A flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
  32. 32.🔺 A 1.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  33. 33.🧮 A 470 Ω resistor is joined in series with two equal 470 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  34. 34.True or false: the ammeter measures voltage. (a) True (b) False
  35. 35.🧮 A 100 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  36. 36.🔺 A current of 50 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  38. 38.🧮 Resistors of 22 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
  39. 39.⚡ A 1.2 W device works on 6 V. What current does it take (in amperes)? =
  40. 40.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?

Answer key

  1. False
  2. a buzzer
  3. 11
  4. 230
  5. energy used each second
  6. 143
  7. 1000
  8. True
  9. 5
  10. 360
  11. False
  12. False
  13. 1.5
  14. 20
  15. 0.75
  16. the one nearest an end
  17. saves electricity
  18. 0.09
  19. 30
  20. 0.25
  21. 0.4
  22. a narrow pipe
  23. R = V ÷ I
  24. 2
  25. 4.7
  26. 76
  27. False
  28. set the AC to 24 °C
  29. 1 kilowatt-hour (kWh)
  30. 4.4
  31. 15
  32. 10
  33. 705
  34. False
  35. 105
  36. 11
  37. cathode (−)
  38. 122
  39. 0.2
  40. 1840

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