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Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 802 · 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.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V + I (c) R = V ÷ I (d) R = V × I
  2. 2.🔺 A current of 10 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.🤖 if (temperature > 34) { show “Hot” } else if (temperature > 23) { show “Warm” } else { show “Cool” }
    The temperature is 26 °C. What is shown?     (a) Hot (b) Warm (c) Cool
  4. 4.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  5. 5.🌐 Each reading a sensor sends is 25 bytes. How many bytes do 140 readings take?
  6. 6.⏱️ A program says “wait 8500 ms”. How many seconds is that? =
  7. 7.🔘 Two switches are in parallel (side by side). When does the bulb glow? (a) only when both are OFF (b) only when both are ON (c) when either is ON (d) never
  8. 8.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
  9. 9.🤖 if (temperature > 34) { show “Hot” } else if (temperature > 26) { show “Warm” } else { show “Cool” }
    The temperature is 25 °C. What is shown?     (a) Warm (b) Hot (c) Cool
  10. 10.🧾 A 200 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
  11. 11.Which of these is an output? (a) a speaker (b) a sound sensor (c) a push button (d) a keypad
  12. 12.🧮 Resistors of 470 Ω, 470 Ω, 330 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
  13. 13.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
  14. 14.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  15. 15.💡 A red LED uses 2 V and should get 10 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
  16. 16.🧭 Which part of a microcontroller board brings power and code? (a) the reset button (b) the main chip (c) the USB port (d) the pins
  17. 17.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) by Wi-Fi (b) in parallel (c) in series (d) not joined
  18. 18.True or false: to make a parking alarm, use a rain sensor. (a) False (b) True
  19. 19.🔋 Identical cells side by side (in parallel) give … (a) no voltage (b) the same voltage (c) double the voltage (d) half the voltage
  20. 20.🔺 A current of 20 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  21. 21.Which of these has no microcontroller inside? (a) a microwave oven (b) a washing machine (c) a digital alarm clock (d) a bicycle bell
  22. 22.🧩 Which component smooths a wobbly supply? (a) buzzer (b) capacitor (c) LDR (d) fuse
  23. 23.🤖 if (light < 300 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 590 and motion is not detected (false). What happens?     (a) porch lamp ON (b) porch lamp OFF
  24. 24.True or false: two or more cell symbols is the symbol for a bulb. (a) True (b) False
  25. 25.What does a diode do? (a) lets current go one way (b) makes a beeping sound (c) smooths a wobbly supply (d) makes things spin
  26. 26.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the if part (b) neither part (c) both parts (d) the else part
  27. 27.🔘 Which kind of switch closes when tipped over? (a) a slide switch (b) a reed switch (c) a push button (d) a tilt switch
  28. 28.⚠️ What protects home wiring by melting or tripping when too much current flows? (a) a long wire (b) a bulb (c) a plug top (d) a fuse or MCB
  29. 29.🧮 Resistors of 68 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
  30. 30.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
  31. 31.⏱️ What does “wait 500 ms” do? (a) pauses for half a second (b) turns the LED off (c) blinks 500 times (d) waits 500 seconds
  32. 32.✏️ Why do engineers draw circuits with symbols? (a) symbols are heavier (b) to hide the circuit (c) quick and clear for all (d) to make it colourful
  33. 33.⚡ A device works on 3 V and takes 2 A. What is its power (in watts)? =
  34. 34.🤖 if (light < 300) { lamp ON } else { lamp OFF }
    The light sensor reads 164. What happens?     (a) lamp OFF (b) lamp ON
  35. 35.🧾 A 500 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
  36. 36.True or false: a slide switch flips up or down. (a) True (b) False
  37. 37.🔌 Is a push button an input or an output for a microcontroller? (a) output (b) input
  38. 38.🌐 Is a Wi-Fi weather station an IoT device? (a) an IoT device (b) not an IoT device
  39. 39.True or false: to dry your hands first is safe. (a) False (b) True
  40. 40.⏱️ How many milliseconds are in 1 second? (a) 10 (b) 1000 (c) 100 (d) 60

Answer key

  1. R = V ÷ I
  2. 1.2
  3. Warm
  4. anode (+)
  5. 3500
  6. 8.5
  7. when either is ON
  8. + (positive)
  9. Cool
  10. 1.2
  11. a speaker
  12. 1490
  13. No
  14. closed
  15. 1000
  16. the USB port
  17. in series
  18. False
  19. the same voltage
  20. 3
  21. a bicycle bell
  22. capacitor
  23. porch lamp OFF
  24. False
  25. lets current go one way
  26. the else part
  27. a tilt switch
  28. a fuse or MCB
  29. 78
  30. saves electricity
  31. pauses for half a second
  32. quick and clear for all
  33. 6
  34. lamp ON
  35. 3
  36. False
  37. input
  38. an IoT device
  39. True
  40. 1000

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