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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 322 · 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 330 Ω resistor is joined in series with two equal 1000 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  2. 2.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
  3. 3.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  4. 4.True or false: a capacitor smooths a wobbly supply. (a) False (b) True
  5. 5.🧾 A 200 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  6. 6.💡 An LED is joined to a 5 V battery through a 470 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) lights up (b) may burn out (c) does not light
  7. 7.🔺 A 12 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  8. 8.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  9. 9.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
  10. 10.🔺 A 2 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  11. 11.True or false: energy used each second is measured in watts (W). (a) False (b) True
  12. 12.📏 How many kilowatts (kW) is 600 W? =
  13. 13.🔺 A 3.3 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  14. 14.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  15. 15.🔺 A 3 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  16. 16.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water pressure (b) the pipe colour (c) the water tank lid (d) the tap handle
  17. 17.🔺 A current of 2.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.🌈 A resistor has the colour bands orange, black, red. What is its value in kilo-ohms (kΩ)? =
  19. 19.📏 How many watts (W) is 2.1 kW?
  20. 20.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  21. 21.🔺 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
  22. 22.🧮 Four equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  23. 23.🔺 A current of 10 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  24. 24.🧩 Which component glows using little power? (a) thermistor (b) LDR (c) resistor (d) LED
  25. 25.🧩 A capacitor in a circuit can … (a) measure heat (b) spin a wheel (c) store charge briefly (d) make light
  26. 26.⚡ 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
  27. 27.⚡ A device works on 9 V and takes 0.2 A. What is its power (in watts)? =
  28. 28.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
  29. 29.⚡ A 4.5 W device works on 3 V. What current does it take (in amperes)? =
  30. 30.🌈 A resistor has the colour bands green, violet, red. What is its value in kilo-ohms (kΩ)? =
  31. 31.🔺 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
  32. 32.🧩 Which component has coloured bands? (a) LDR (b) resistor (c) fuse (d) thermistor
  33. 33.🔺 A current of 50 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.🔺 An 8 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  35. 35.🧮 Resistors of 50 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
  36. 36.⚡ A device works on 1.5 V and takes 0.25 A. What is its power (in watts)? =
  37. 37.Which of these saves electricity? (a) use old filament bulbs (b) use LED lamps (c) leave fridge door open (d) leave the TV on standby
  38. 38.⚡ A device works on 1.5 V and takes 0.2 A. What is its power (in watts)? =
  39. 39.⚡ A device works on 6 V and takes 0.1 A. What is its power (in watts)? =
  40. 40.🌈 A resistor has the colour bands green, green, orange. What is its value (in ohms)?

Answer key

  1. 830
  2. saves electricity
  3. anode (+)
  4. True
  5. 0.4
  6. does not light
  7. 1.5
  8. 230
  9. saves electricity
  10. 0.1
  11. True
  12. 0.6
  13. 10
  14. cathode (−)
  15. 20
  16. the water pressure
  17. 15
  18. 3
  19. 2100
  20. 4
  21. I = V ÷ R
  22. 50
  23. 3
  24. LED
  25. store charge briefly
  26. energy used each second
  27. 1.8
  28. 920
  29. 1.5
  30. 5.7
  31. R = V ÷ I
  32. resistor
  33. 5
  34. 40
  35. 150
  36. 0.375
  37. use LED lamps
  38. 0.3
  39. 0.6
  40. 55000

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