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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 530 · 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.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
  2. 2.📏 How many kilo-ohms (kΩ) is 8000 Ω? =
  3. 3.🔺 A current of 20 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  4. 4.🔺 A current of 40 mA flows when 4.8 V is joined across a resistor. What is its resistance (in ohms)?
  5. 5.Which of these is measured in ohms (Ω)? (a) the push of a cell (b) resistance (c) voltage (d) the flow of charge
  6. 6.🌈 A resistor has the colour bands red, blue, red. What is its value in kilo-ohms (kΩ)? =
  7. 7.True or false: the voltmeter is joined across a part. (a) True (b) False
  8. 8.🔺 A current of 1.5 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
  9. 9.Which of these wastes electricity? (a) set the AC to 24 °C (b) use daylight to read (c) close the fridge quickly (d) iron one shirt at a time
  10. 10.🧾 A family uses 130 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
  11. 11.🧮 A 100 Ω resistor is joined in series with two equal 470 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  12. 12.⚡ Power tells us … (a) the colour of light (b) the length of a wire (c) the size of a cell (d) energy used each second
  13. 13.Which of these wastes electricity? (a) set the AC to 24 °C (b) leave the TV on standby (c) use daylight to read (d) use LED lamps
  14. 14.True or false: the voltmeter is joined in series. (a) True (b) False
  15. 15.What does an LDR do? (a) is a resistance knob (b) makes a beeping sound (c) senses how hot it is (d) senses how bright it is
  16. 16.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 7300 Ω resistor? (a) violet-orange-brown (b) violet-orange-red (c) violet-orange-orange (d) orange-violet-red
  17. 17.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) a candle (c) an oil lamp (d) an LED lamp
  18. 18.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to store charge (c) to make it brighter (d) to limit the current
  19. 19.🧮 A 470 Ω resistor is joined in series with two equal 330 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  20. 20.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 5 % (c) 0 % (d) 50 %
  21. 21.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) becomes zero (c) stays the same (d) gets bigger
  22. 22.🔺 A current of 20 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
  23. 23.Which of these is measured in ohms (Ω)? (a) how much a part resists (b) voltage (c) the flow of charge (d) current
  24. 24.🔺 A current of 1 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  25. 25.🧩 Which component glows using little power? (a) transistor (b) LED (c) capacitor (d) diode
  26. 26.True or false: on an LED, the longer leg is the cathode (−). (a) False (b) True
  27. 27.🔺 A current of 0.1 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  28. 28.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  29. 29.🔺 A current of 10 mA flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.True or false: the ammeter is joined in series. (a) False (b) True
  31. 31.🌈 A resistor has the colour bands violet, violet, orange. What is its value (in ohms)?
  32. 32.🔺 A current of 0.2 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.🧮 Resistors of 20 Ω, 22 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
  34. 34.⚡ A device works on 12 V and takes 0.2 A. What is its power (in watts)? =
  35. 35.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  36. 36.🔍 Which is the odd one out? (a) leave fridge door open (b) switch off empty rooms (c) close the fridge quickly (d) use LED lamps
  37. 37.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter
  38. 38.📏 How many milliamperes (mA) is 0.82 A?
  39. 39.💡 What does LED stand for? (a) large electric dial (b) light energy dial (c) low energy device (d) light-emitting diode
  40. 40.⚡ A device works on 1.5 V and takes 0.5 A. What is its power (in watts)? =

Answer key

  1. wastes electricity
  2. 8
  3. 200
  4. 120
  5. resistance
  6. 2.6
  7. True
  8. 8
  9. iron one shirt at a time
  10. 1040
  11. 335
  12. energy used each second
  13. leave the TV on standby
  14. False
  15. senses how bright it is
  16. violet-orange-red
  17. an LED lamp
  18. to limit the current
  19. 635
  20. 5 %
  21. gets smaller
  22. 5
  23. how much a part resists
  24. 15
  25. LED
  26. False
  27. 1.5
  28. 1
  29. 120
  30. True
  31. 77000
  32. 2.4
  33. 52
  34. 2.4
  35. cathode (−)
  36. leave fridge door open
  37. voltmeter
  38. 820
  39. light-emitting diode
  40. 0.75

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