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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 910 · 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.🧩 A capacitor in a circuit can … (a) spin a wheel (b) measure heat (c) store charge briefly (d) make light
  2. 2.True or false: to iron one shirt at a time wastes electricity. (a) False (b) True
  3. 3.🔺 A current of 50 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  4. 4.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) zero (c) stay the same (d) bigger
  5. 5.💡 An LED is joined to a 3 V battery through a 330 Ω 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
  6. 6.🧮 Resistors of 100 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
  7. 7.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  8. 8.🔺 A current of 50 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  9. 9.🔺 A 10 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  10. 10.🧮 Two equal 50 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  11. 11.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) False (b) True
  12. 12.🧩 Which component smooths a wobbly supply? (a) buzzer (b) potentiometer (c) capacitor (d) resistor
  13. 13.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V × I (d) P = V + I
  14. 14.📏 In the water-pipe picture of a circuit, current is like … (a) the water pressure (b) a narrow pipe (c) the pipe colour (d) the flow of water
  15. 15.🔺 A 5 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  16. 16.📏 Which unit measures energy used each second? (a) ohm (Ω) (b) watt (W) (c) volt (V) (d) ampere (A)
  17. 17.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
  18. 18.🧾 A family uses 100 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
  19. 19.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 46 Ω resistor? (a) yellow-blue-brown (b) yellow-blue-black (c) blue-yellow-black (d) green-blue-black
  20. 20.🔺 A 10 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  21. 21.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it changes colour (c) it does not light (d) it makes a sound
  22. 22.True or false: a capacitor smooths a wobbly supply. (a) False (b) True
  23. 23.🌈 A resistor has the colour bands white, grey, yellow. What is its value in kilo-ohms (kΩ)? =
  24. 24.🧩 Which component has coloured bands? (a) potentiometer (b) thermistor (c) capacitor (d) resistor
  25. 25.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1000 (b) 10 (c) 1024 (d) 100
  26. 26.🌈 A resistor has the colour bands yellow, green, orange. What is its value (in ohms)?
  27. 27.🔺 A current of 40 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  28. 28.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  29. 29.📏 How many kilowatts (kW) is 3950 W? =
  30. 30.True or false: the flow of charge is measured in amperes (A). (a) True (b) False
  31. 31.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  32. 32.🔺 A 3 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  33. 33.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = V × I (c) R = V ÷ I (d) R = I ÷ V
  34. 34.True or false: to use LED lamps saves electricity. (a) True (b) False
  35. 35.True or false: the flow of charge is measured in watts (W). (a) False (b) True
  36. 36.🌈 A resistor has the colour bands white, white, orange. What is its value (in ohms)?
  37. 37.⚡ 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
  38. 38.🧾 A family uses 130 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  39. 39.🌈 Which band is read first on a resistor? (a) any band (b) the one nearest an end (c) the widest gap (d) the gold band
  40. 40.💡 An LED is joined to a 12 V battery with no resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) may burn out (b) lights up (c) does not light

Answer key

  1. store charge briefly
  2. True
  3. 5
  4. bigger
  5. lights up
  6. 150
  7. 50
  8. 11
  9. 50
  10. 25
  11. True
  12. capacitor
  13. P = V × I
  14. the flow of water
  15. 0.5
  16. watt (W)
  17. wastes electricity
  18. 500
  19. yellow-blue-black
  20. 25
  21. it does not light
  22. True
  23. 980
  24. resistor
  25. 1000
  26. 45000
  27. 250
  28. cathode (−)
  29. 3.95
  30. True
  31. 4
  32. 0.2
  33. R = V ÷ I
  34. True
  35. False
  36. 99000
  37. energy used each second
  38. 520
  39. the one nearest an end
  40. may burn out

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