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Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 877 · 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.🔐 Is it a good or a risky habit to turn off unused gadgets? (a) risky habit (b) good habit
  2. 2.Which of these is a conductor? (a) a dry cork (b) a metal paper clip (c) a woollen thread (d) a glass marble
  3. 3.🔋 On a cell, does “usually the black wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
  4. 4.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
  5. 5.✏️ Why do engineers draw circuits with symbols? (a) symbols are heavier (b) quick and clear for all (c) to make it colourful (d) to hide the circuit
  6. 6.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 0 % (c) 5 % (d) 25 %
  7. 7.Which of these is an IoT device? (a) a plain table fan (b) a fitness band with app (c) a wind-up clock (d) a pencil sharpener
  8. 8.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in series (b) by Wi-Fi (c) in parallel (d) not joined
  9. 9.📶 A pin that reads a push button is set as … (a) a battery (b) an input (c) an output (d) a resistor
  10. 10.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  11. 11.Which of these usually has a microcontroller inside? (a) a candle (b) a hand pump (c) a spinning top (d) a TV remote
  12. 12.📏 Which unit measures power? (a) ampere (A) (b) ohm (Ω) (c) watt (W) (d) volt (V)
  13. 13.True or false: an LED glows using little power. (a) False (b) True
  14. 14.🧩 A capacitor in a circuit can … (a) store charge briefly (b) make light (c) spin a wheel (d) measure heat
  15. 15.🔘 Which kind of switch slides side to side? (a) a reed switch (b) a push button (c) a slide switch (d) a tilt switch
  16. 16.🧩 Which component smooths a wobbly supply? (a) diode (b) LED (c) buzzer (d) capacitor
  17. 17.⚡ Power tells us … (a) the length of a wire (b) the size of a cell (c) the colour of light (d) energy used each second
  18. 18.⏱️ repeat 3 times { buzzer ON; wait 1000 ms; buzzer OFF; wait 700 ms }
    How many milliseconds does this take in all?
  19. 19.🔋 Cells joined + to − in a row (series) give … (a) no voltage (b) a bigger voltage (c) the same voltage (d) a smaller voltage
  20. 20.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) an open circuit (c) a full circuit (d) a closed circuit
  21. 21.⏱️ loop forever { LED ON; wait 1000 ms; LED OFF; wait 150 ms }
    How many milliseconds does one blink (ON + OFF) take?
  22. 22.True or false: “compare with a limit” is the process. (a) True (b) False
  23. 23.🤖 if (temperature > 25) { fan ON } else { fan OFF }
    The temperature sensor reads 33 °C. What happens?     (a) fan ON (b) fan OFF
  24. 24.💡 An LED is joined to a 9 V battery with no resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) lights up (b) may burn out (c) does not light
  25. 25.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 6 V supply. What current flows (in mA)?
  26. 26.⚡ A device works on 9 V and takes 0.5 A. What is its power (in watts)? =
  27. 27.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  28. 28.🔺 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
  29. 29.💡 What does LED stand for? (a) low energy device (b) large electric dial (c) light-emitting diode (d) light energy dial
  30. 30.True or false: to close the fridge quickly wastes electricity. (a) True (b) False
  31. 31.⏱️ loop forever { LED ON; wait 550 ms; LED OFF; wait 600 ms }
    How many milliseconds does one blink (ON + OFF) take?
  32. 32.💡 A red LED uses 2 V and should get 25 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
  33. 33.True or false: two equal parallel lines is the symbol for a cell. (a) True (b) False
  34. 34.Which of these mainly gives out light? (a) a water heater (b) a doorbell (c) a torch (d) a buzzer
  35. 35.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
  36. 36.💡 Does it save or waste electricity to leave fridge door open? (a) wastes electricity (b) saves electricity
  37. 37.Which of these is an input? (a) a speaker (b) an LED (c) a motor (d) a sound sensor
  38. 38.True or false: how much a part resists is measured in volts (V). (a) False (b) True
  39. 39.⚙️ What is an actuator? (a) an output that acts (b) a program (c) a sensor (d) a battery
  40. 40.🔺 A current of 10 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =

Answer key

  1. good habit
  2. a metal paper clip
  3. − (negative)
  4. Yes
  5. quick and clear for all
  6. 5 %
  7. a fitness band with app
  8. in series
  9. an input
  10. 230
  11. a TV remote
  12. watt (W)
  13. True
  14. store charge briefly
  15. a slide switch
  16. capacitor
  17. energy used each second
  18. 5100
  19. a bigger voltage
  20. an open circuit
  21. 1150
  22. True
  23. fan ON
  24. may burn out
  25. 20
  26. 4.5
  27. anode (+)
  28. V = I × R
  29. light-emitting diode
  30. False
  31. 1150
  32. 280
  33. False
  34. a torch
  35. 2300
  36. wastes electricity
  37. a sound sensor
  38. False
  39. an output that acts
  40. 2.2

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