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Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 120 · 40 questions
TalentJR

Remember (Find the topic, use the idea): Find the topic: circuit, safety, formula, component, program, sensor or IoT. Use that lesson’s rule — complete loop, V = I × R, P = V × I, last command wins, true → if part. Safety answers are always: low voltage, dry hands, an adult, never the mains.

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  1. 1.🔺 A 3 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  2. 2.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I × R (c) V = I + R (d) V = I ÷ R
  3. 3.🔁 x = 1
    repeat 1 time { x = x × 2 }
    What is x at the end?
  4. 4.⚡ Which formula gives electric power? (a) P = V × I (b) P = I ÷ V (c) P = V ÷ I (d) P = V + I
  5. 5.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
  6. 6.🔁 What does “count = count + 1” do? (a) adds 1 to count (b) takes 1 away (c) prints 1 (d) sets count to 1
  7. 7.🔁 count = 5
    while (count < 20) { count = count + 5 }
    How many times does the loop run?
  8. 8.What does a motor do? (a) beeps for an alarm (b) senses how bright it is (c) turns a fan or wheels (d) stores a little charge
  9. 9.Which of these mainly gives out heat? (a) a torch (b) a night lamp (c) a room heater (d) a loudspeaker
  10. 10.What does a push button do? (a) closes near a magnet (b) stays where you flip it (c) works only while pressed (d) closes when tipped over
  11. 11.🔢 To get a sensor reading onto a phone, which is the LAST step? (a) the cloud stores it (b) the app shows it (c) it is sent by Wi-Fi (d) the sensor measures
  12. 12.Which of these is an output? (a) a turning knob (b) a sound sensor (c) a speaker (d) a push button
  13. 13.💡 A battery lights 2 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) brighter (b) the same (c) dimmer
  14. 14.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
  15. 15.🔐 Is it a good or a risky habit to set a strong password? (a) risky habit (b) good habit
  16. 16.True or false: on an LED, the leg by the flat edge is the anode (+). (a) True (b) False
  17. 17.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
  18. 18.True or false: “bulbs share the voltage” is true of a parallel circuit. (a) False (b) True
  19. 19.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the process (b) the battery (c) the output (d) the input
  20. 20.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  21. 21.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 2.5 V supply. What current flows (in mA)?
  22. 22.🔋 How many 1.2 V cells must be joined in series to give 7.2 V?
  23. 23.🔌 Is a metal paper clip a conductor or an insulator? (a) an insulator (b) a conductor
  24. 24.🔍 Which is the odd one out? (a) an exhaust fan (b) an electric drill (c) a loudspeaker (d) an electric toy car
  25. 25.🔌 Is a dry cork a conductor or an insulator? (a) an insulator (b) a conductor
  26. 26.True or false: a laptop has a built-in keyboard. (a) False (b) True
  27. 27.Which of these is measured in watts (W)? (a) current (b) the push of a cell (c) the flow of charge (d) energy used each second
  28. 28.✏️ Why do engineers draw circuits with symbols? (a) to hide the circuit (b) symbols are heavier (c) quick and clear for all (d) to make it colourful
  29. 29.🔺 A current of 25 mA flows when 11.75 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.Which of these has no microcontroller inside? (a) a smart watch (b) a microwave oven (c) a toy robot (d) a hand pump
  31. 31.🤖 Does a digital thermometer usually have a microcontroller inside? (a) No (b) Yes
  32. 32.✏️ In a circuit diagram, wires are usually drawn as … (a) wavy lines (b) dotted circles (c) straight lines (d) little stars
  33. 33.🌈 A resistor has the colour bands red, blue, red. What is its value (in ohms)?
  34. 34.🔋 On a cell, does “the shorter symbol line” mean the + end or the − end? (a) + (positive) (b) − (negative)
  35. 35.🌐 How does a home IoT device usually send its data to the app? (a) by shouting (b) over Wi-Fi (c) by post (d) through a candle
  36. 36.Which of these is true of a parallel circuit? (a) one bulb out, all go out (b) a break stops every bulb (c) each gets the full volts (d) a single current path
  37. 37.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  38. 38.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) + (positive) (b) − (negative)
  39. 39.True or false: to start a fan when hot, use a temperature sensor. (a) False (b) True
  40. 40.True or false: “one bulb out, all go out” is true of a series circuit. (a) True (b) False

Answer key

  1. 25
  2. V = I × R
  3. 2
  4. P = V × I
  5. False
  6. adds 1 to count
  7. 3
  8. turns a fan or wheels
  9. a room heater
  10. works only while pressed
  11. the app shows it
  12. a speaker
  13. dimmer
  14. Yes
  15. good habit
  16. False
  17. 460
  18. False
  19. the process
  20. anode (+)
  21. 5
  22. 6
  23. a conductor
  24. a loudspeaker
  25. an insulator
  26. True
  27. energy used each second
  28. quick and clear for all
  29. 470
  30. a hand pump
  31. Yes
  32. straight lines
  33. 2600
  34. − (negative)
  35. over Wi-Fi
  36. each gets the full volts
  37. False
  38. + (positive)
  39. True
  40. True

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