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Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 933 · 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.Which drawing is the symbol for an ammeter? (a) a dot where wires meet (b) a circle with A inside (c) one tall, one short bar (d) a circle with M inside
  2. 2.⚡ Which formula gives electric power? (a) P = V × I (b) P = V ÷ I (c) P = I ÷ V (d) P = V + I
  3. 3.🌈 A resistor has the colour bands violet, red, brown. What is its value (in ohms)?
  4. 4.Which of these is a good habit? (a) change default passwords (b) reuse one password (c) share the Wi-Fi key (d) accept every permission
  5. 5.🔋 How many 2 V cells must be joined in series to give 14 V?
  6. 6.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  7. 7.🔢 To run one loop of a plant-watering program, which is the LAST step? (a) compare with the limit (b) wait a few seconds (c) read the soil sensor (d) switch the pump on/off
  8. 8.Which of these is true of a parallel circuit? (a) bulbs share the voltage (b) a break stops every bulb (c) many paths for current (d) a single current path
  9. 9.⚠️ Is it safe to use small battery cells? (a) not safe (b) safe
  10. 10.⏱️ repeat 8 times { buzzer ON; wait 700 ms; buzzer OFF; wait 1000 ms }
    How many milliseconds does this take in all?
  11. 11.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 7 LOW
    set pin 7 LOW
    set pin 7 LOW
    set pin 8 HIGH
    Is the LED ON or OFF at the end?     (a) OFF (b) ON
  12. 12.🔺 A current of 0.25 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  13. 13.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they keep glowing (b) they get dimmer (c) they explode (d) they all go out
  14. 14.🔘 A cell and a bulb are joined to 2 side-by-side paths with one switch on each path — A and B (parallel). A is OFF and B is ON. Does the bulb glow? (a) No (b) Yes
  15. 15.⚠️ Is it safe to poke things in a socket? (a) safe (b) not safe
  16. 16.💡 6 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 2 is taken out of its holder. Does bulb 3 glow? (a) Yes (b) No
  17. 17.🔘 Which kind of switch closes when tipped over? (a) a tilt switch (b) a toggle switch (c) a push button (d) a reed switch
  18. 18.🌈 In the resistor colour code, which number does brown stand for?
  19. 19.💡 Why is house wiring done in parallel? (a) each gets full voltage (b) to save copper only (c) to make bulbs dim (d) so all go off together
  20. 20.🔺 A 12 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  21. 21.🔁 x = 1
    repeat 5 times { x = x × 2 }
    What is x at the end?
  22. 22.🔌 Most metals are good … (a) conductors (b) insulators (c) magnets only (d) batteries
  23. 23.True or false: to use small battery cells is safe. (a) False (b) True
  24. 24.⚡ A 2.4 W device works on 24 V. What current does it take (in amperes)? =
  25. 25.True or false: a reed switch stays where you flip it. (a) False (b) True
  26. 26.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 8 LOW
    set pin 8 LOW
    Is the LED ON or OFF at the end?     (a) ON (b) OFF
  27. 27.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  28. 28.🌈 Which band is read first on a resistor? (a) the widest gap (b) the one nearest an end (c) the gold band (d) any band
  29. 29.⏱️ loop forever { LED ON; wait 350 ms; LED OFF; wait 650 ms }
    How many times does the LED blink in 9 seconds?
  30. 30.🔺 A current of 10 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  31. 31.True or false: “one bulb out, all go out” is true of a parallel circuit. (a) False (b) True
  32. 32.True or false: an LED lamp mainly gives out light. (a) False (b) True
  33. 33.✏️ In a circuit diagram, wires are usually drawn as … (a) straight lines (b) wavy lines (c) little stars (d) dotted circles
  34. 34.True or false: to start a fan when hot, use a temperature sensor. (a) False (b) True
  35. 35.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a steel spoon. Does the bulb glow? (a) No (b) Yes
  36. 36.⏱️ loop forever { LED ON; wait 300 ms; LED OFF; wait 350 ms }
    How many milliseconds does one blink (ON + OFF) take?
  37. 37.Which of these is an input? (a) a servo motor (b) a light sensor (c) a motor (d) a buzzer
  38. 38.🔺 A current of 2.5 A flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
  39. 39.Which of these is a risky habit? (a) install software updates (b) post your live location (c) cover unused cameras (d) set a strong password
  40. 40.True or false: how much a part resists is measured in volts (V). (a) True (b) False

Answer key

  1. a circle with A inside
  2. P = V × I
  3. 720
  4. change default passwords
  5. 7
  6. 4
  7. wait a few seconds
  8. many paths for current
  9. safe
  10. 13600
  11. OFF
  12. 1.25
  13. they keep glowing
  14. Yes
  15. not safe
  16. No
  17. a tilt switch
  18. 1
  19. each gets full voltage
  20. 1
  21. 32
  22. conductors
  23. True
  24. 0.1
  25. False
  26. OFF
  27. anode (+)
  28. the one nearest an end
  29. 9
  30. 400
  31. False
  32. True
  33. straight lines
  34. True
  35. Yes
  36. 650
  37. a light sensor
  38. 3
  39. post your live location
  40. False

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