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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 605 · 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.🧮 Resistors of 470 Ω, 50 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
  2. 2.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
  3. 3.📏 In the water-pipe picture of a circuit, resistance is like … (a) the flow of water (b) a narrow pipe (c) the water pressure (d) a bigger tank
  4. 4.Which of these wastes electricity? (a) set the AC to 24 °C (b) close the fridge quickly (c) unplug idle chargers (d) iron one shirt at a time
  5. 5.🔺 A 9 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  6. 6.True or false: the ammeter is joined across a part. (a) True (b) False
  7. 7.🧩 Which component senses how hot it is? (a) LDR (b) thermistor (c) LED (d) diode
  8. 8.🧮 A 1.5 V battery is joined to 4 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
  9. 9.📏 Which unit measures the flow of charge? (a) ampere (A) (b) ohm (Ω) (c) volt (V) (d) watt (W)
  10. 10.🌈 A resistor has the colour bands grey, brown, brown. What is its value (in ohms)?
  11. 11.🔺 A current of 50 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  12. 12.📏 How many kilo-ohms (kΩ) is 5400 Ω? =
  13. 13.🔺 A current of 0.2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  14. 14.⚡ A device works on 1.5 V and takes 0.25 A. What is its power (in watts)? =
  15. 15.⚡ A device works on 5 V and takes 0.25 A. What is its power (in watts)? =
  16. 16.🧾 A family uses 50 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
  17. 17.📏 How many amperes (A) is 2900 mA? =
  18. 18.🧮 Resistors of 150 Ω, 330 Ω, 10 Ω and 22 Ω are joined in series. What is the total resistance (in ohms)?
  19. 19.💡 Why does an LED need a resistor in series? (a) to limit the current (b) to make it brighter (c) to change its colour (d) to store charge
  20. 20.🧮 Resistors of 220 Ω, 470 Ω and 47 Ω are joined in series. What is the total resistance (in ohms)?
  21. 21.What does a thermistor do? (a) senses how bright it is (b) beeps for an alarm (c) senses how hot it is (d) is a resistance knob
  22. 22.🧾 A family uses 120 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
  23. 23.💡 What does LED stand for? (a) low energy device (b) light-emitting diode (c) light energy dial (d) large electric dial
  24. 24.🧮 Resistors of 10 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
  25. 25.📏 How many amperes (A) is 1820 mA? =
  26. 26.🔺 A current of 0.25 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  27. 27.🌈 A resistor has the colour bands grey, violet, orange. What is its value (in ohms)?
  28. 28.🧮 A 2.25 V battery is joined to 4 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
  29. 29.True or false: to unplug idle chargers saves electricity. (a) True (b) False
  30. 30.🔺 A 0.75 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  31. 31.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
  32. 32.⚡ Power tells us … (a) energy used each second (b) the size of a cell (c) the length of a wire (d) the colour of light
  33. 33.True or false: an LDR senses how bright it is. (a) True (b) False
  34. 34.🧮 A 0.7 V battery is joined to 2 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
  35. 35.🔺 A 2 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  36. 36.🔺 A 10 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  37. 37.🔺 A current of 0.1 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.🔺 A current of 2.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  39. 39.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 5600 Ω resistor? (a) green-blue-orange (b) green-blue-brown (c) blue-green-red (d) green-blue-red
  40. 40.🧩 Which component limits the current? (a) resistor (b) buzzer (c) fuse (d) LDR

Answer key

  1. 740
  2. 115
  3. a narrow pipe
  4. iron one shirt at a time
  5. 1.5
  6. False
  7. thermistor
  8. 0.25
  9. ampere (A)
  10. 810
  11. 100
  12. 5.4
  13. 0.8
  14. 0.375
  15. 1.25
  16. 300
  17. 2.9
  18. 512
  19. to limit the current
  20. 737
  21. senses how hot it is
  22. 960
  23. light-emitting diode
  24. 60
  25. 1.82
  26. 1.5
  27. 87000
  28. 0.25
  29. True
  30. 0.25
  31. False
  32. energy used each second
  33. True
  34. 0.1
  35. 1
  36. 1
  37. 0.8
  38. 25
  39. green-blue-red
  40. resistor

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