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Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 769 · 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.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 300 ms }
    How many times does the LED blink in 20 seconds?
  2. 2.🧮 A 22 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  3. 3.🧩 Which part changes electrical energy into sound? (a) a diode (b) a buzzer (c) a capacitor (d) a resistor
  4. 4.Which of these is an insulator? (a) a metal paper clip (b) aluminium foil (c) a graphite rod (d) a rubber eraser
  5. 5.✏️ In a circuit diagram, which part is drawn as a line lifted at a gap? (a) battery (b) resistor (c) bulb (d) switch
  6. 6.🔁 count = 0
    repeat 2 times { count = count + 5 }
    What is count at the end?
  7. 7.🔦 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 dry cork. Does the bulb glow? (a) No (b) Yes
  8. 8.🔍 A distance sensor sends a sound pulse and hears the echo 11 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
  9. 9.True or false: a toggle switch stays where you flip it. (a) True (b) False
  10. 10.True or false: the flow of charge is measured in volts (V). (a) True (b) False
  11. 11.Which of these is an input? (a) a small display (b) a speaker (c) an LED (d) a keypad
  12. 12.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  13. 13.🔌 Is a steel coin a conductor or an insulator? (a) an insulator (b) a conductor
  14. 14.🌈 In the resistor colour code, which number does violet stand for?
  15. 15.Which of these has no microcontroller inside? (a) a toy robot (b) a microwave oven (c) a digital thermometer (d) a spinning top
  16. 16.🔁 x = 4
    repeat 3 times { x = x × 2 }
    What is x at the end?
  17. 17.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) only one (c) both of them (d) none
  18. 18.✏️ In a cell symbol, which line is the + terminal? (a) both lines (b) the shorter line (c) neither line (d) the longer line
  19. 19.🔋 Cells joined + to − in a row (series) give … (a) a bigger voltage (b) the same voltage (c) no voltage (d) a smaller voltage
  20. 20.True or false: a toaster mainly gives out heat. (a) False (b) True
  21. 21.🔍 Which is the odd one out? (a) a Wi-Fi doorbell camera (b) a smart energy meter (c) a paper calendar (d) a Wi-Fi weather station
  22. 22.True or false: to set up with a parent is a good habit. (a) True (b) False
  23. 23.🌈 A resistor has the colour bands white, black, yellow. What is its value in kilo-ohms (kΩ)? =
  24. 24.🔺 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
  25. 25.⚠️ A cell gets hot when its + and − ends are joined by a bare wire. What is this called? (a) a short circuit (b) a safe circuit (c) a parallel circuit (d) an open circuit
  26. 26.🤖 When the main loop of a microcontroller program ends, what happens? (a) it stops forever (b) it deletes itself (c) it starts again (d) the board breaks
  27. 27.🤖 if (temperature > 25) { fan ON } else { fan OFF }
    The temperature sensor reads 28 °C. What happens?     (a) fan ON (b) fan OFF
  28. 28.🔁 count = 1
    while (count < 10) { count = count + 3 }
    How many times does the loop run?
  29. 29.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. A gap in one wire is bridged by a dry cork. Does the bulb glow? (a) No (b) Yes
  30. 30.True or false: a rice cooker mainly makes movement. (a) True (b) False
  31. 31.Which of these is not safe? (a) dry your hands first (b) build with an adult near (c) use mains for a project (d) keep drinks far away
  32. 32.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) − (negative) (b) + (positive)
  33. 33.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the battery (b) the input (c) the output (d) the process
  34. 34.🧩 Which component stores a little charge? (a) transistor (b) capacitor (c) potentiometer (d) buzzer
  35. 35.💡 Why is house wiring done in parallel? (a) each gets full voltage (b) so all go off together (c) to make bulbs dim (d) to save copper only
  36. 36.True or false: on an LED, the longer leg is the cathode (−). (a) False (b) True
  37. 37.Which of these is an output? (a) a motion sensor (b) a keypad (c) a sound sensor (d) a water pump
  38. 38.⏱️ loop forever { LED ON; wait 50 ms; LED OFF; wait 150 ms }
    How many times does the LED blink in 4 seconds?
  39. 39.🌈 In the resistor colour code, which number does orange stand for?
  40. 40.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False

Answer key

  1. 50
  2. 132
  3. a buzzer
  4. a rubber eraser
  5. switch
  6. 10
  7. No
  8. 187
  9. True
  10. False
  11. a keypad
  12. 20
  13. a conductor
  14. 7
  15. a spinning top
  16. 32
  17. both of them
  18. the longer line
  19. a bigger voltage
  20. True
  21. a paper calendar
  22. True
  23. 900
  24. V = I × R
  25. a short circuit
  26. it starts again
  27. fan ON
  28. 3
  29. No
  30. False
  31. use mains for a project
  32. + (positive)
  33. the process
  34. capacitor
  35. each gets full voltage
  36. False
  37. a water pump
  38. 20
  39. 3
  40. False

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