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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 957 · 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.📏 Which unit measures the flow of charge? (a) watt (W) (b) ohm (Ω) (c) ampere (A) (d) volt (V)
  2. 2.🌈 A resistor has the colour bands white, red, red. What is its value (in ohms)?
  3. 3.⚡ A device works on 9 V and takes 0.5 A. What is its power (in watts)? =
  4. 4.📏 How many kilo-ohms (kΩ) is 2300 Ω? =
  5. 5.🔍 Which is the odd one out? (a) use old filament bulbs (b) run fans in empty rooms (c) leave the TV on standby (d) set the AC to 24 °C
  6. 6.🔺 A current of 50 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  7. 7.🧮 A 1.8 V battery is joined to 8 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
  8. 8.🔺 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
  9. 9.⚡ Which formula gives electric power? (a) P = V + I (b) P = I ÷ V (c) P = V × I (d) P = V ÷ I
  10. 10.🧾 A family uses 80 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  11. 11.🔍 Which is the odd one out? (a) unplug idle chargers (b) leave fridge door open (c) iron one shirt at a time (d) leave the TV on standby
  12. 12.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  13. 13.🔺 A current of 50 mA flows when 11 V is joined across a resistor. What is its resistance (in ohms)?
  14. 14.📏 Which unit measures resistance? (a) volt (V) (b) ampere (A) (c) watt (W) (d) ohm (Ω)
  15. 15.🌈 A resistor has the colour bands orange, red, orange. What is its value in kilo-ohms (kΩ)? =
  16. 16.🔺 A current of 2 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  17. 17.🧾 A 250 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  18. 18.🔺 An 8 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  19. 19.🔺 A 9.4 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  20. 20.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 watt (c) 1 kilowatt-hour (kWh) (d) 1 ampere
  21. 21.🔺 A current of 0.1 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  22. 22.True or false: voltage is measured in ohms (Ω). (a) True (b) False
  23. 23.📏 In the water-pipe picture of a circuit, resistance is like … (a) the water pressure (b) a bigger tank (c) a narrow pipe (d) the flow of water
  24. 24.🌈 In the resistor colour code, which number does brown stand for?
  25. 25.⚡ A device works on 12 V and takes 1.5 A. What is its power (in watts)? =
  26. 26.What does a buzzer do? (a) turns a fan or wheels (b) lets current go one way (c) beeps for an alarm (d) makes things spin
  27. 27.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 85 Ω resistor? (a) grey-green-brown (b) green-grey-black (c) white-green-black (d) grey-green-black
  28. 28.True or false: the ammeter is joined in series. (a) False (b) True
  29. 29.🧮 A 20 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)?
  30. 30.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) smaller (c) stay the same (d) zero
  31. 31.What does a capacitor do? (a) senses how hot it is (b) limits the current (c) makes things spin (d) stores a little charge
  32. 32.What does an LDR do? (a) stores a little charge (b) senses how bright it is (c) has coloured bands (d) boosts a small signal
  33. 33.🔺 A 1 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  34. 34.🔺 A 30 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  35. 35.Which of these is measured in amperes (A)? (a) power (b) current (c) voltage (d) how much a part resists
  36. 36.🌈 A resistor has the colour bands red, brown, red. What is its value in kilo-ohms (kΩ)? =
  37. 37.🔺 A 16.5 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  38. 38.🔺 A 7.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  39. 39.🔺 A current of 0.25 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 98 Ω resistor? (a) grey-white-black (b) brown-grey-black (c) white-grey-brown (d) white-grey-black

Answer key

  1. ampere (A)
  2. 9200
  3. 4.5
  4. 2.3
  5. set the AC to 24 °C
  6. 100
  7. 0.1
  8. I = V ÷ R
  9. P = V × I
  10. 720
  11. unplug idle chargers
  12. anode (+)
  13. 220
  14. ohm (Ω)
  15. 32
  16. 10
  17. 0.5
  18. 20
  19. 20
  20. 1 kilowatt-hour (kWh)
  21. 0.6
  22. False
  23. a narrow pipe
  24. 1
  25. 18
  26. beeps for an alarm
  27. grey-green-black
  28. True
  29. 255
  30. bigger
  31. stores a little charge
  32. senses how bright it is
  33. 0.2
  34. 2.5
  35. current
  36. 2.1
  37. 50
  38. 0.5
  39. 1.5
  40. white-grey-black

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