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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 411 · 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 68 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 40 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.True or false: to run fans in empty rooms saves electricity. (a) True (b) False
  4. 4.🧩 Which part changes electrical energy into sound? (a) a diode (b) a capacitor (c) a buzzer (d) a resistor
  5. 5.🧩 A capacitor in a circuit can … (a) store charge briefly (b) make light (c) measure heat (d) spin a wheel
  6. 6.🔺 A current of 10 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  7. 7.🔺 A current of 1 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.⚡ A device works on 1.5 V and takes 0.1 A. What is its power (in watts)? =
  9. 9.🧮 Two resistors in parallel give a total that is … (a) always zero (b) less than either one (c) their sum (d) more than either one
  10. 10.🔺 A current of 3 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  11. 11.⚡ A 6 W device works on 6 V. What current does it take (in amperes)? =
  12. 12.💡 What happens if an LED is put in backwards? (a) it makes a sound (b) it lights brighter (c) it does not light (d) it changes colour
  13. 13.🔺 A current of 0.1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  14. 14.True or false: to run fans in empty rooms wastes electricity. (a) True (b) False
  15. 15.🔺 A current of 50 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  16. 16.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an oil lamp (c) a candle (d) an LED lamp
  17. 17.🧮 Three equal 30 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  18. 18.🔺 A 10 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  19. 19.⚡ Power tells us … (a) the size of a cell (b) energy used each second (c) the length of a wire (d) the colour of light
  20. 20.🧮 A 16 V battery is joined to 8 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
  21. 21.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  22. 22.⚡ A 0.375 W device works on 1.5 V. What current does it take (in amperes)? =
  23. 23.🔺 A current of 10 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
  24. 24.🔺 A current of 0.25 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  25. 25.🔺 A current of 0.2 A flows when 0.8 V is joined across a resistor. What is its resistance (in ohms)?
  26. 26.🧾 A family uses 190 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  27. 27.💡 An LED is joined to a 5 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) may burn out (c) does not light
  28. 28.📏 How many ohms (Ω) is 8.3 kΩ?
  29. 29.Which of these wastes electricity? (a) close the fridge quickly (b) iron one shirt at a time (c) use LED lamps (d) use daylight to read
  30. 30.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
  31. 31.📏 How many milliamperes (mA) make 1 ampere? (a) 100 (b) 60 (c) 1000 (d) 10
  32. 32.🔺 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
  33. 33.🔺 A 6 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
  34. 34.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 25 % (c) 5 % (d) 0 %
  35. 35.🧾 A 200 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  36. 36.🌈 In the resistor colour code, which number does brown stand for?
  37. 37.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
  38. 38.True or false: an LED smooths a wobbly supply. (a) False (b) True
  39. 39.🔺 A current of 0.5 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  40. 40.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) bigger (c) zero (d) stay the same

Answer key

  1. 178
  2. 18.8
  3. False
  4. a buzzer
  5. store charge briefly
  6. 2
  7. 15
  8. 0.15
  9. less than either one
  10. 15
  11. 1
  12. it does not light
  13. 1
  14. True
  15. 11
  16. an LED lamp
  17. 10
  18. 25
  19. energy used each second
  20. 1
  21. 10
  22. 0.25
  23. 5
  24. 1.5
  25. 4
  26. 1710
  27. may burn out
  28. 8300
  29. iron one shirt at a time
  30. ammeter
  31. 1000
  32. R = V ÷ I
  33. 20
  34. 5 %
  35. 2
  36. 1
  37. 1150
  38. False
  39. 6
  40. bigger

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