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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 632 · 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.What does a resistor do? (a) beeps for an alarm (b) has coloured bands (c) senses how bright it is (d) makes things spin
  2. 2.True or false: a capacitor makes a beeping sound. (a) False (b) True
  3. 3.🧮 A 220 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)?
  4. 4.🔺 A 0.6 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  5. 5.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 180 Ω resistor? (a) brown-grey-black (b) brown-grey-brown (c) brown-grey-red (d) grey-brown-brown
  6. 6.⚡ A 6 W device works on 12 V. What current does it take (in amperes)? =
  7. 7.⚡ A device works on 6 V and takes 1.5 A. What is its power (in watts)? =
  8. 8.🧮 A 330 Ω resistor is joined in series with two equal 50 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  9. 9.🔺 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
  10. 10.🔺 A 4.8 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  11. 11.⚡ A 27 W device works on 9 V. What current does it take (in amperes)? =
  12. 12.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  13. 13.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a capacitor (c) a diode (d) a resistor
  14. 14.🔺 A current of 0.5 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.True or false: the voltmeter is joined across a part. (a) False (b) True
  16. 16.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 0 % (c) 50 % (d) 5 %
  17. 17.Which of these is measured in volts (V)? (a) voltage (b) current (c) how much a part resists (d) energy used each second
  18. 18.🔺 A current of 10 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
  19. 19.📏 How many milliamperes (mA) make 1 ampere? (a) 100 (b) 60 (c) 1000 (d) 10
  20. 20.🌈 A resistor has the colour bands red, brown, black. What is its value (in ohms)?
  21. 21.⚡ A 0.75 W device works on 1.5 V. What current does it take (in amperes)? =
  22. 22.⚡ Power tells us … (a) the size of a cell (b) the length of a wire (c) the colour of light (d) energy used each second
  23. 23.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
  24. 24.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = I ÷ R (c) V = I × R (d) V = R ÷ I
  25. 25.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  26. 26.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  27. 27.What does a fuse do? (a) has coloured bands (b) senses how bright it is (c) blows if current is high (d) smooths a wobbly supply
  28. 28.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
  29. 29.🔍 Which is the odd one out? (a) leave the TV on standby (b) iron one shirt at a time (c) leave fridge door open (d) switch off empty rooms
  30. 30.🧾 A 100 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
  31. 31.🧾 A family uses 20 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  32. 32.Which of these saves electricity? (a) leave the TV on standby (b) close the fridge quickly (c) run fans in empty rooms (d) leave fridge door open
  33. 33.🔺 A 0.8 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  34. 34.🧩 Which component has coloured bands? (a) potentiometer (b) resistor (c) buzzer (d) diode
  35. 35.🧮 Resistors of 330 Ω, 47 Ω and 470 Ω are joined in series. What is the total resistance (in ohms)?
  36. 36.📏 Which unit measures resistance? (a) ohm (Ω) (b) ampere (A) (c) volt (V) (d) watt (W)
  37. 37.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  38. 38.🌈 In the resistor colour code, which number does red stand for?
  39. 39.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.⚡ A device works on 1.5 V and takes 3 A. What is its power (in watts)? =

Answer key

  1. has coloured bands
  2. False
  3. 385
  4. 0.1
  5. brown-grey-brown
  6. 0.5
  7. 9
  8. 355
  9. I = V ÷ R
  10. 40
  11. 3
  12. cathode (−)
  13. a buzzer
  14. 12
  15. True
  16. 5 %
  17. voltage
  18. 1.2
  19. 1000
  20. 21
  21. 0.5
  22. energy used each second
  23. ammeter
  24. V = I × R
  25. 500
  26. 230
  27. blows if current is high
  28. 460
  29. switch off empty rooms
  30. 0.6
  31. 80
  32. close the fridge quickly
  33. 0.2
  34. resistor
  35. 847
  36. ohm (Ω)
  37. 5
  38. 2
  39. 4
  40. 4.5

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