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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 862 · 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.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 watt (c) 1 kilowatt-hour (kWh) (d) 1 volt
  2. 2.Which of these saves electricity? (a) leave the TV on standby (b) run fans in empty rooms (c) use LED lamps (d) iron one shirt at a time
  3. 3.True or false: to use old filament bulbs wastes electricity. (a) False (b) True
  4. 4.True or false: the flow of charge is measured in ohms (Ω). (a) False (b) True
  5. 5.🧾 A family uses 20 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  6. 6.True or false: a resistor has coloured bands. (a) False (b) True
  7. 7.🔺 A current of 25 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.🧩 A capacitor in a circuit can … (a) make light (b) spin a wheel (c) measure heat (d) store charge briefly
  9. 9.True or false: to switch off empty rooms wastes electricity. (a) True (b) False
  10. 10.🧮 Resistors of 22 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
  11. 11.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) smaller (c) stay the same (d) zero
  12. 12.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  13. 13.Which of these saves electricity? (a) run fans in empty rooms (b) leave the TV on standby (c) leave fridge door open (d) use daylight to read
  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) does not light (b) may burn out (c) lights up
  15. 15.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 540 Ω resistor? (a) green-yellow-black (b) green-yellow-red (c) yellow-green-brown (d) green-yellow-brown
  16. 16.🧩 Which component senses how bright it is? (a) LDR (b) transistor (c) buzzer (d) resistor
  17. 17.⚡ A device works on 1.5 V and takes 0.25 A. What is its power (in watts)? =
  18. 18.💡 A red LED uses 2 V and should get 10 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
  19. 19.🧩 Which part changes electrical energy into movement? (a) a resistor (b) an LED (c) a fuse (d) a motor
  20. 20.🔺 A 4 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  21. 21.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = V ÷ R (c) I = V + R (d) I = R ÷ V
  22. 22.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  23. 23.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets bigger (c) becomes zero (d) gets smaller
  24. 24.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter
  25. 25.⚡ A device works on 3 V and takes 0.25 A. What is its power (in watts)? =
  26. 26.⚡ A 5 W device works on 5 V. What current does it take (in amperes)? =
  27. 27.🧩 Which component turns a fan or wheels? (a) resistor (b) potentiometer (c) fuse (d) motor
  28. 28.🔺 A current of 3 A flows when 18 V is joined across a resistor. What is its resistance (in ohms)?
  29. 29.🔺 A current of 20 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.🔺 A current of 25 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  31. 31.🔺 A current of 0.25 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  32. 32.🔺 A 3 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  33. 33.🔺 A current of 3 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.🧾 Which lamp gives the same light for the least power? (a) an LED lamp (b) a candle (c) an oil lamp (d) a filament bulb
  35. 35.🧮 A 47 Ω resistor is joined in series with two equal 200 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  36. 36.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I ÷ R (c) V = I × R (d) V = I + R
  37. 37.🧮 A 1.4 V battery is joined to 5 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
  38. 38.🔺 A current of 2.5 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  39. 39.⚡ A 9 W device works on 6 V. What current does it take (in amperes)? =
  40. 40.🔺 A current of 0.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =

Answer key

  1. 1 kilowatt-hour (kWh)
  2. use LED lamps
  3. True
  4. False
  5. 180
  6. True
  7. 8.25
  8. store charge briefly
  9. False
  10. 172
  11. bigger
  12. 230
  13. use daylight to read
  14. does not light
  15. green-yellow-brown
  16. LDR
  17. 0.375
  18. 400
  19. a motor
  20. 2
  21. I = V ÷ R
  22. cathode (−)
  23. gets smaller
  24. voltmeter
  25. 0.75
  26. 1
  27. motor
  28. 6
  29. 400
  30. 7.5
  31. 3
  32. 1.5
  33. 30
  34. an LED lamp
  35. 147
  36. V = I × R
  37. 0.2
  38. 2
  39. 1.5
  40. 3

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