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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 319 · 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 formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V + I (d) P = V × I
  2. 2.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V × R (c) I = V ÷ R (d) I = V + R
  3. 3.Which of these saves electricity? (a) unplug idle chargers (b) leave the TV on standby (c) use old filament bulbs (d) iron one shirt at a time
  4. 4.🔺 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
  5. 5.True or false: power is measured in watts (W). (a) True (b) False
  6. 6.🔺 A current of 10 mA flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
  7. 7.🔺 A current of 0.1 A flows when 0.8 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) becomes zero (c) gets smaller (d) stays the same
  9. 9.📏 How many watts (W) is 0.8 kW?
  10. 10.🔺 A current of 1.5 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  11. 11.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
  12. 12.⚡ Power tells us … (a) the size of a cell (b) the colour of light (c) the length of a wire (d) energy used each second
  13. 13.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  14. 14.🔺 A current of 0.1 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.🧾 A family uses 40 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
  16. 16.🧮 Two resistors in parallel give a total that is … (a) their sum (b) more than either one (c) always zero (d) less than either one
  17. 17.🔺 A current of 0.25 A flows when 0.5 V is joined across a resistor. What is its resistance (in ohms)?
  18. 18.⚡ A 2.25 W device works on 9 V. What current does it take (in amperes)? =
  19. 19.⚡ A device works on 24 V and takes 3 A. What is its power (in watts)? =
  20. 20.🔺 A current of 0.2 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  21. 21.🧾 A 100 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
  22. 22.🌈 A resistor has the colour bands brown, blue, red. What is its value (in ohms)?
  23. 23.🧾 A 100 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
  24. 24.📏 In the water-pipe picture of a circuit, voltage is like … (a) the pipe colour (b) the water tank lid (c) the water pressure (d) the tap handle
  25. 25.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) bigger (c) stay the same (d) smaller
  26. 26.🔺 A 0.6 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  27. 27.🔺 A current of 0.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  28. 28.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
  29. 29.📏 How many milliamperes (mA) is 2.63 A?
  30. 30.📏 How many ohms (Ω) is 5 kΩ?
  31. 31.🔺 A current of 3 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  32. 32.🔺 A current of 0.5 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  33. 33.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
  34. 34.🧾 A 1500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  35. 35.🔺 A current of 10 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  36. 36.🔺 A current of 0.25 A flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
  37. 37.🌈 In the resistor colour code, which number does blue stand for?
  38. 38.True or false: on an LED, the leg by the flat edge is the anode (+). (a) True (b) False
  39. 39.🧾 One “unit” on an electricity bill is … (a) 1 kilowatt-hour (kWh) (b) 1 watt (c) 1 volt (d) 1 ampere
  40. 40.🔺 A current of 3 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =

Answer key

  1. P = V × I
  2. I = V ÷ R
  3. unplug idle chargers
  4. V = I × R
  5. True
  6. 150
  7. 8
  8. gets smaller
  9. 800
  10. 4
  11. False
  12. energy used each second
  13. 230
  14. 10
  15. 200
  16. less than either one
  17. 2
  18. 0.25
  19. 72
  20. 1.6
  21. 0.8
  22. 1600
  23. 0.5
  24. the water pressure
  25. bigger
  26. 0.2
  27. 2
  28. 1150
  29. 2630
  30. 5000
  31. 24
  32. 20
  33. saves electricity
  34. 3
  35. 3
  36. 6
  37. 6
  38. False
  39. 1 kilowatt-hour (kWh)
  40. 9

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