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Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 814 · 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.

NameDateTime takenScore ___ / 40
  1. 1.True or false: on a cell, “the flat end” means the + (positive) end. (a) False (b) True
  2. 2.⏱️ loop forever { LED ON; wait 900 ms; LED OFF; wait 600 ms }
    How many milliseconds does one blink (ON + OFF) take?
  3. 3.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  4. 4.🔋 4 identical 3 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
  5. 5.⚠️ Is it safe to build with an adult near? (a) safe (b) not safe
  6. 6.🔍 Which is the odd one out? (a) a table fan (b) a ceiling fan (c) a night lamp (d) a mixer grinder
  7. 7.🧩 Which component senses how bright it is? (a) LED (b) LDR (c) transistor (d) resistor
  8. 8.🔋 A 6 V battery and one 1.5 V cell are joined in series, all facing the same way. What is the total voltage (in volts)? =
  9. 9.⏱️ repeat 8 times { buzzer ON; wait 600 ms; buzzer OFF; wait 100 ms }
    How many milliseconds does this take in all?
  10. 10.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 900 ms }
    How many times does the LED blink in 9 seconds?
  11. 11.🧮 Two resistors in parallel give a total that is … (a) their sum (b) always zero (c) less than either one (d) more than either one
  12. 12.⚙️ Which actuator would you use to show the temperature? (a) a display (b) an LED (c) a buzzer (d) a servo motor
  13. 13.🌐 A weather station sends one reading every 60 seconds. How many readings does it send in 2 minutes?
  14. 14.🔺 A current of 50 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  15. 15.🔁 What does a variable do in a program? (a) measures light (b) blinks an LED (c) stores a value (d) joins two wires
  16. 16.⚙️ Which actuator would you use to beep an alarm? (a) a servo motor (b) a buzzer (c) an LED (d) a motor
  17. 17.🔘 A bulb and a cell are joined through 6 switches one after another in a single loop (series). What is the smallest number of switches that must be ON to light the bulb?
  18. 18.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1000 (b) 10 (c) 1024 (d) 100
  19. 19.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) smaller (c) stay the same (d) bigger
  20. 20.🔺 A current of 20 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  21. 21.🤖 if (temperature > 31) { show “Hot” } else if (temperature > 19) { show “Warm” } else { show “Cool” }
    The temperature is 45 °C. What is shown?     (a) Hot (b) Cool (c) Warm
  22. 22.🔘 Two switches are in parallel (side by side). When does the bulb glow? (a) only when both are OFF (b) never (c) only when both are ON (d) when either is ON
  23. 23.🔍 Which is the odd one out? (a) share the Wi-Fi key (b) accept every permission (c) change default passwords (d) share camera links
  24. 24.🌈 A resistor has the colour bands green, violet, yellow. What is its value in kilo-ohms (kΩ)? =
  25. 25.🔍 For a microcontroller, is a sensor an input or an output? (a) a fuse (b) an output (c) an input (d) a power source
  26. 26.🔺 A 30 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  27. 27.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V + I (c) P = V × I (d) P = I ÷ V
  28. 28.True or false: a buzzer stores a little charge. (a) True (b) False
  29. 29.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3.5 V supply. What current flows (in mA)?
  30. 30.🔁 count = 4
    repeat 4 times { count = count + 3 }
    What is count at the end?
  31. 31.Which of these uses electricity? (a) a computer (b) a bicycle dynamo (c) a cell (d) a wind turbine
  32. 32.💡 6 identical bulbs are in parallel and each one takes 0.5 A. What total current (in amperes) comes from the battery? =
  33. 33.Which of these is not an IoT device? (a) a Wi-Fi weather station (b) a Wi-Fi doorbell camera (c) an app-controlled bulb (d) a plain table fan
  34. 34.🤖 Which is a safe power source for a beginner microcontroller board? (a) bare mains wires (b) a wall socket directly (c) USB or a 9 V battery (d) a 230 V cable
  35. 35.🔍 Which sensor would you use to start a fan when hot? (a) a gas sensor (b) a distance sensor (c) a light sensor (d) a temperature sensor
  36. 36.🧮 Resistors of 220 Ω, 22 Ω, 150 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
  37. 37.Which of these is a conductor? (a) a dry cork (b) a wooden stick (c) an iron nail (d) a woollen thread
  38. 38.True or false: “a break stops every bulb” is true of a series circuit. (a) False (b) True
  39. 39.⚡ A fan changes electrical energy mainly into which kind of energy? (a) chemical energy (b) movement energy (c) light energy (d) sound energy
  40. 40.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the process (b) the output (c) the input (d) the battery

Answer key

  1. False
  2. 1500
  3. open
  4. 12
  5. safe
  6. a night lamp
  7. LDR
  8. 7.5
  9. 5600
  10. 9
  11. less than either one
  12. a display
  13. 2
  14. 7.5
  15. stores a value
  16. a buzzer
  17. 6
  18. 1000
  19. bigger
  20. 3
  21. Hot
  22. when either is ON
  23. change default passwords
  24. 570
  25. an input
  26. 3
  27. P = V × I
  28. False
  29. 15
  30. 16
  31. a computer
  32. 3
  33. a plain table fan
  34. USB or a 9 V battery
  35. a temperature sensor
  36. 425
  37. an iron nail
  38. True
  39. movement energy
  40. the process

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