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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 506 · 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 family uses 30 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  2. 2.⚡ Power tells us … (a) energy used each second (b) the colour of light (c) the length of a wire (d) the size of a cell
  3. 3.Which of these wastes electricity? (a) use LED lamps (b) switch off empty rooms (c) iron one shirt at a time (d) set the AC to 24 °C
  4. 4.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  5. 5.🧮 Resistors of 330 Ω, 33 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
  6. 6.🔺 A current of 20 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  7. 7.🔺 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
  8. 8.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 ampere (c) 1 watt (d) 1 kilowatt-hour (kWh)
  9. 9.🧾 A 200 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  10. 10.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 880 Ω resistor? (a) grey-grey-red (b) grey-grey-brown (c) grey-grey-black (d) grey-white-brown
  11. 11.🧾 A family uses 40 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  12. 12.🔺 A current of 25 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  13. 13.🔺 A current of 20 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  14. 14.⚡ A device works on 6 V and takes 0.1 A. What is its power (in watts)? =
  15. 15.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a diode (c) a resistor (d) a capacitor
  16. 16.🌈 A resistor has the colour bands orange, blue, orange. What is its value (in ohms)?
  17. 17.What does a capacitor do? (a) glows using little power (b) beeps for an alarm (c) turns a fan or wheels (d) stores a little charge
  18. 18.🔺 A 0.4 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  19. 19.🔺 A current of 25 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  20. 20.🔍 Which is the odd one out? (a) use LED lamps (b) set the AC to 24 °C (c) unplug idle chargers (d) iron one shirt at a time
  21. 21.Which of these is measured in amperes (A)? (a) power (b) voltage (c) the flow of charge (d) resistance
  22. 22.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  23. 23.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
  24. 24.📏 Which unit measures current? (a) watt (W) (b) ampere (A) (c) ohm (Ω) (d) volt (V)
  25. 25.⚡ A device works on 5 V and takes 2 A. What is its power (in watts)? =
  26. 26.🧮 A 330 Ω resistor is joined in series with two equal 100 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  27. 27.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
  28. 28.⚡ A device works on 24 V and takes 3 A. What is its power (in watts)? =
  29. 29.🧮 A 15 V battery is joined to 3 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  30. 30.True or false: to use old filament bulbs saves electricity. (a) True (b) False
  31. 31.🔺 A current of 50 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  32. 32.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 5 V supply. What current flows (in mA)?
  33. 33.🔺 A current of 50 mA flows when 16.5 V is joined across a resistor. What is its resistance (in ohms)?
  34. 34.🧮 Five equal 125 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  35. 35.🌈 A resistor has the colour bands violet, yellow, red. What is its value in kilo-ohms (kΩ)? =
  36. 36.🧩 Which component limits the current? (a) LDR (b) potentiometer (c) buzzer (d) resistor
  37. 37.📏 Which unit measures resistance? (a) ohm (Ω) (b) watt (W) (c) ampere (A) (d) volt (V)
  38. 38.What does a buzzer do? (a) lets current go one way (b) makes a beeping sound (c) limits the current (d) smooths a wobbly supply
  39. 39.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = R ÷ V (c) I = V + R (d) I = V × R
  40. 40.💡 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) lights up (b) does not light (c) may burn out

Answer key

  1. 120
  2. energy used each second
  3. iron one shirt at a time
  4. 100
  5. 513
  6. 6.6
  7. V = I × R
  8. 1 kilowatt-hour (kWh)
  9. 0.8
  10. grey-grey-brown
  11. 360
  12. 10
  13. 2
  14. 0.6
  15. a buzzer
  16. 36000
  17. stores a little charge
  18. 0.1
  19. 7.5
  20. iron one shirt at a time
  21. the flow of charge
  22. cathode (−)
  23. wastes electricity
  24. ampere (A)
  25. 10
  26. 380
  27. voltmeter
  28. 72
  29. 1
  30. False
  31. 120
  32. 10
  33. 330
  34. 25
  35. 7.4
  36. resistor
  37. ohm (Ω)
  38. makes a beeping sound
  39. I = V ÷ R
  40. may burn out

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