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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 562 · 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 happens if an LED is put in backwards? (a) it makes a sound (b) it does not light (c) it lights brighter (d) it changes colour
  2. 2.🔺 A current of 0.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.⚡ A device works on 1.5 V and takes 0.5 A. What is its power (in watts)? =
  4. 4.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
  5. 5.True or false: to leave the TV on standby saves electricity. (a) False (b) True
  6. 6.🌈 In the resistor colour code, which number does red stand for?
  7. 7.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 0 % (c) 50 % (d) 5 %
  8. 8.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
  9. 9.🔺 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
  10. 10.🌈 A resistor has the colour bands blue, green, brown. What is its value (in ohms)?
  11. 11.⚡ A device works on 12 V and takes 2 A. What is its power (in watts)? =
  12. 12.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
  13. 13.True or false: to use daylight to read wastes electricity. (a) True (b) False
  14. 14.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  15. 15.🧾 A family uses 70 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  16. 16.Which of these wastes electricity? (a) unplug idle chargers (b) run fans in empty rooms (c) set the AC to 24 °C (d) use daylight to read
  17. 17.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) False (b) True
  18. 18.⚡ A 6 W device works on 6 V. What current does it take (in amperes)? =
  19. 19.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3 V supply. What current flows (in mA)?
  20. 20.Which of these is measured in volts (V)? (a) how much a part resists (b) the push of a cell (c) power (d) the flow of charge
  21. 21.Which of these is measured in ohms (Ω)? (a) energy used each second (b) voltage (c) the flow of charge (d) how much a part resists
  22. 22.True or false: a resistor has coloured bands. (a) True (b) False
  23. 23.🧮 Resistors of 330 Ω, 10 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
  24. 24.🔺 A current of 20 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  25. 25.⚡ A device works on 24 V and takes 0.1 A. What is its power (in watts)? =
  26. 26.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  27. 27.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
  28. 28.What does a diode do? (a) limits the current (b) lets current go one way (c) turns a fan or wheels (d) is a resistance knob
  29. 29.🔺 A current of 2.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  30. 30.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = I ÷ V (c) R = V × I (d) R = V ÷ I
  31. 31.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
  32. 32.📏 Which unit measures voltage? (a) ohm (Ω) (b) ampere (A) (c) volt (V) (d) watt (W)
  33. 33.⚡ A 15 W device works on 5 V. What current does it take (in amperes)? =
  34. 34.🌈 A resistor has the colour bands white, violet, yellow. What is its value in kilo-ohms (kΩ)? =
  35. 35.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
  36. 36.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  37. 37.🔺 A current of 40 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.📏 How many watts (W) is 2.2 kW?
  39. 39.🔺 A 1 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  40. 40.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a diode (c) a capacitor (d) a buzzer

Answer key

  1. it does not light
  2. 5
  3. 0.75
  4. saves electricity
  5. False
  6. 2
  7. 5 %
  8. 2300
  9. I = V ÷ R
  10. 650
  11. 24
  12. 115
  13. False
  14. 230
  15. 280
  16. run fans in empty rooms
  17. True
  18. 1
  19. 10
  20. the push of a cell
  21. how much a part resists
  22. True
  23. 360
  24. 3
  25. 2.4
  26. 165
  27. True
  28. lets current go one way
  29. 37.5
  30. R = V ÷ I
  31. False
  32. volt (V)
  33. 3
  34. 970
  35. 170
  36. 50
  37. 8.8
  38. 2200
  39. 0.2
  40. a buzzer

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