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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 867 · 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 100 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  2. 2.🔺 A current of 20 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
  4. 4.📏 How many kilo-ohms (kΩ) is 5300 Ω? =
  5. 5.Which of these is measured in amperes (A)? (a) resistance (b) the push of a cell (c) voltage (d) current
  6. 6.🌈 Which band is read first on a resistor? (a) any band (b) the gold band (c) the widest gap (d) the one nearest an end
  7. 7.🔺 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
  8. 8.🧮 A 100 Ω resistor is joined in series with two equal 20 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  9. 9.⚡ A device works on 12 V and takes 0.25 A. What is its power (in watts)? =
  10. 10.🧩 Which component smooths a wobbly supply? (a) diode (b) thermistor (c) resistor (d) capacitor
  11. 11.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 97000 Ω resistor? (a) violet-white-orange (b) white-violet-red (c) white-violet-yellow (d) white-violet-orange
  12. 12.🧮 A 330 Ω resistor is joined in series with two equal 20 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  13. 13.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a filament bulb (c) a candle (d) an LED lamp
  14. 14.🔺 A 4.8 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  15. 15.True or false: a diode lets current go one way. (a) False (b) True
  16. 16.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I × R (c) V = R ÷ I (d) V = I + R
  17. 17.⚡ A device works on 5 V and takes 0.1 A. What is its power (in watts)? =
  18. 18.🧩 A capacitor in a circuit can … (a) store charge briefly (b) measure heat (c) spin a wheel (d) make light
  19. 19.Which of these wastes electricity? (a) iron one shirt at a time (b) close the fridge quickly (c) use LED lamps (d) use daylight to read
  20. 20.What does a motor do? (a) boosts a small signal (b) senses how hot it is (c) has coloured bands (d) makes things spin
  21. 21.🧮 A 33 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)?
  22. 22.True or false: the voltmeter measures voltage. (a) True (b) False
  23. 23.⚡ A 0.75 W device works on 1.5 V. What current does it take (in amperes)? =
  24. 24.Which of these saves electricity? (a) iron one shirt at a time (b) use old filament bulbs (c) leave fridge door open (d) use daylight to read
  25. 25.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
  26. 26.True or false: to set the AC to 24 °C wastes electricity. (a) True (b) False
  27. 27.🔍 Which is the odd one out? (a) switch off empty rooms (b) unplug idle chargers (c) use old filament bulbs (d) use LED lamps
  28. 28.🔺 A current of 20 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
  29. 29.🔺 A current of 20 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.🧮 Two resistors in parallel give a total that is … (a) always zero (b) their sum (c) less than either one (d) more than either one
  31. 31.⚡ Power tells us … (a) energy used each second (b) the length of a wire (c) the colour of light (d) the size of a cell
  32. 32.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a resistor (c) a motor (d) an LED
  33. 33.📏 In the water-pipe picture of a circuit, resistance is like … (a) the water pressure (b) a bigger tank (c) the flow of water (d) a narrow pipe
  34. 34.🧾 A family uses 140 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  35. 35.🔺 A current of 0.1 A flows when 0.6 V is joined across a resistor. What is its resistance (in ohms)?
  36. 36.🔺 A current of 0.1 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.True or false: to switch off empty rooms saves electricity. (a) False (b) True
  38. 38.⚡ A 6 W device works on 3 V. What current does it take (in amperes)? =
  39. 39.🔺 A current of 10 mA flows when 4.7 V is joined across a resistor. What is its resistance (in ohms)?
  40. 40.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets smaller (d) gets bigger

Answer key

  1. 210
  2. 3
  3. 595
  4. 5.3
  5. current
  6. the one nearest an end
  7. I = V ÷ R
  8. 110
  9. 3
  10. capacitor
  11. white-violet-orange
  12. 340
  13. an LED lamp
  14. 40
  15. True
  16. V = I × R
  17. 0.5
  18. store charge briefly
  19. iron one shirt at a time
  20. makes things spin
  21. 38
  22. True
  23. 0.5
  24. use daylight to read
  25. False
  26. False
  27. use old filament bulbs
  28. 5
  29. 150
  30. less than either one
  31. energy used each second
  32. a motor
  33. a narrow pipe
  34. 560
  35. 6
  36. 2
  37. True
  38. 2
  39. 470
  40. gets smaller

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