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Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 422 · 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 current of 0.1 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  2. 2.🔺 A current of 0.1 A flows when 0.2 V is joined across a resistor. What is its resistance (in ohms)?
  3. 3.True or false: “each gets the full volts” is true of a series circuit. (a) True (b) False
  4. 4.⏱️ repeat 2 times { buzzer ON; wait 700 ms; buzzer OFF; wait 200 ms }
    How many milliseconds does this take in all?
  5. 5.⚠️ A cell gets hot when its + and − ends are joined by a bare wire. What is this called? (a) a parallel circuit (b) an open circuit (c) a short circuit (d) a safe circuit
  6. 6.🗺️ In an input → process → output plan, is “decide if soil is dry” the input, the process or the output? (a) process (b) input (c) output
  7. 7.True or false: the voltmeter measures voltage. (a) True (b) False
  8. 8.🤖 Does a smart watch usually have a microcontroller inside? (a) No (b) Yes
  9. 9.🌈 A resistor has the colour bands red, black, yellow. What is its value in kilo-ohms (kΩ)? =
  10. 10.🧮 Four equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  11. 11.True or false: to share the Wi-Fi key is a good habit. (a) False (b) True
  12. 12.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V ÷ I (d) P = V × I
  13. 13.⏱️ A program says “wait 3000 ms”. How many seconds is that? =
  14. 14.🔺 A current of 10 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
  15. 15.🔍 Which is the odd one out? (a) log out of shared phones (b) keep factory passwords (c) turn off unused gadgets (d) change default passwords
  16. 16.🔌 Is a motion sensor an input or an output for a microcontroller? (a) input (b) output
  17. 17.Which of these is true of a series circuit? (a) one out, the rest glow (b) one bulb out, all go out (c) own switch for each bulb (d) used in house wiring
  18. 18.True or false: a motor has coloured bands. (a) True (b) False
  19. 19.True or false: “own switch for each bulb” is true of a parallel circuit. (a) True (b) False
  20. 20.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a plastic straw across the gap. Does the bulb glow? (a) Yes (b) No
  21. 21.Which of these mainly makes movement? (a) an exhaust fan (b) a water heater (c) a rice cooker (d) a street light
  22. 22.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) bigger (c) zero (d) stay the same
  23. 23.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
  24. 24.🤖 if (temperature > 32) { show “Hot” } else if (temperature > 24) { show “Warm” } else { show “Cool” }
    The temperature is 21 °C. What is shown?     (a) Warm (b) Hot (c) Cool
  25. 25.🤖 if (light < 400 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 450 and motion is not detected (false). What happens?     (a) porch lamp OFF (b) porch lamp ON
  26. 26.🔁 repeat 5 times { repeat 2 times { beep } }
    How many beeps are there?
  27. 27.What does a motor do? (a) boosts a small signal (b) makes things spin (c) makes a beeping sound (d) blows if current is high
  28. 28.Which of these is safe? (a) build with an adult near (b) fly a kite near wires (c) poke things in a socket (d) open a phone charger
  29. 29.🔍 Which sensor would you use to open blinds at sunrise? (a) a sound sensor (b) a rain sensor (c) a soil moisture sensor (d) a light sensor
  30. 30.True or false: to use daylight to read saves electricity. (a) True (b) False
  31. 31.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 5 V supply. What current flows (in mA)?
  32. 32.⏱️ loop forever { LED ON; wait 950 ms; LED OFF; wait 1000 ms }
    How many milliseconds does one blink (ON + OFF) take?
  33. 33.⏱️ A program says “wait 3250 ms”. How many seconds is that? =
  34. 34.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water tank lid (b) the pipe colour (c) the water pressure (d) the tap handle
  35. 35.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = R ÷ I (c) V = I × R (d) V = I + R
  36. 36.Which of these is true of a series circuit? (a) a single current path (b) each gets the full volts (c) own switch for each bulb (d) one out, the rest glow
  37. 37.True or false: on a cell, “usually the black wire” means the + (positive) end. (a) False (b) True
  38. 38.🔺 A current of 10 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  39. 39.True or false: on an LED, the round-side leg is the anode (+). (a) False (b) True
  40. 40.🤖 if (light < 200 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 400 and motion is detected (true). What happens?     (a) porch lamp OFF (b) porch lamp ON

Answer key

  1. 0.5
  2. 2
  3. False
  4. 1800
  5. a short circuit
  6. process
  7. True
  8. Yes
  9. 200
  10. 50
  11. False
  12. P = V × I
  13. 3
  14. 4.7
  15. keep factory passwords
  16. input
  17. one bulb out, all go out
  18. False
  19. True
  20. No
  21. an exhaust fan
  22. bigger
  23. saves electricity
  24. Cool
  25. porch lamp OFF
  26. 10
  27. makes things spin
  28. build with an adult near
  29. a light sensor
  30. True
  31. 15
  32. 1950
  33. 3.25
  34. the water pressure
  35. V = I × R
  36. a single current path
  37. False
  38. 1.5
  39. True
  40. porch lamp ON

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