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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 764 · 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 2.2 V battery is joined to 6 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
  2. 2.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I × R (c) V = R ÷ I (d) V = I + R
  3. 3.True or false: how much a part resists is measured in volts (V). (a) False (b) True
  4. 4.True or false: on an LED, the longer leg is the anode (+). (a) True (b) False
  5. 5.Which of these saves electricity? (a) leave fridge door open (b) iron one shirt at a time (c) leave the TV on standby (d) unplug idle chargers
  6. 6.True or false: to run fans in empty rooms saves electricity. (a) True (b) False
  7. 7.💡 An LED is joined to a 9 V battery through a 1000 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
  8. 8.💡 An LED is joined to a 9 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) lights up (b) does not light (c) may burn out
  9. 9.💡 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
  10. 10.🔺 A 3.75 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  11. 11.🧮 A 20 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)?
  12. 12.⚡ A device works on 5 V and takes 1.5 A. What is its power (in watts)? =
  13. 13.🔺 A current of 40 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  14. 14.🔍 Which is the odd one out? (a) use daylight to read (b) close the fridge quickly (c) run fans in empty rooms (d) unplug idle chargers
  15. 15.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 0 % (c) 50 % (d) 25 %
  16. 16.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
  17. 17.🧾 A family uses 20 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
  18. 18.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 84 Ω resistor? (a) yellow-grey-black (b) grey-yellow-brown (c) white-yellow-black (d) grey-yellow-black
  19. 19.🔺 A current of 20 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  20. 20.🧾 A family uses 80 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  21. 21.🌈 A resistor has the colour bands grey, brown, orange. What is its value (in ohms)?
  22. 22.🧮 A 2.5 V battery is joined to 8 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
  23. 23.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
  24. 24.Which of these is measured in volts (V)? (a) the push of a cell (b) power (c) resistance (d) how much a part resists
  25. 25.True or false: a capacitor turns a fan or wheels. (a) True (b) False
  26. 26.📏 Which unit measures the push of a cell? (a) volt (V) (b) watt (W) (c) ampere (A) (d) ohm (Ω)
  27. 27.⚡ A device works on 6 V and takes 0.2 A. What is its power (in watts)? =
  28. 28.📏 How many ohms (Ω) is 2.2 kΩ?
  29. 29.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = I ÷ V (c) P = V + I (d) P = V × I
  30. 30.🔺 A 25 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
  31. 31.🔺 A 2 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  32. 32.🧮 Resistors of 330 Ω and 47 Ω are joined in series. What is the total resistance (in ohms)?
  33. 33.🔺 A current of 1.5 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
  34. 34.⚡ A device works on 12 V and takes 0.1 A. What is its power (in watts)? =
  35. 35.🔺 A 1.2 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  36. 36.🔺 A current of 1 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.🔺 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
  38. 38.🔺 A 1 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  39. 39.🔺 A 2.5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  40. 40.⚡ Power tells us … (a) the colour of light (b) the size of a cell (c) energy used each second (d) the length of a wire

Answer key

  1. 0.2
  2. V = I × R
  3. False
  4. True
  5. unplug idle chargers
  6. False
  7. lights up
  8. lights up
  9. it does not light
  10. 0.25
  11. 130
  12. 7.5
  13. 4
  14. run fans in empty rooms
  15. 5 %
  16. ammeter
  17. 120
  18. grey-yellow-black
  19. 400
  20. 720
  21. 81000
  22. 0.25
  23. 300
  24. the push of a cell
  25. False
  26. volt (V)
  27. 1.2
  28. 2200
  29. P = V × I
  30. 50
  31. 10
  32. 377
  33. 8
  34. 1.2
  35. 0.2
  36. 20
  37. R = V ÷ I
  38. 0.25
  39. 10
  40. energy used each second

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