Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 867 · 40 questions

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.

1. 1.⚙️ Which actuator would you use to beep an alarm? (a) a motor (b) a buzzer (c) a servo motor (d) an LED
2. 2.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
   set pin 7 HIGH
   set pin 8 HIGH
   set pin 8 HIGH
   set pin 7 LOW
   Is the LED ON or OFF at the end? (a) ON (b) OFF
3. 3.📏 Which unit measures how much a part resists? (a) ohm (Ω) (b) volt (V) (c) ampere (A) (d) watt (W)
4. 4.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
5. 5.📏 How many kilo-ohms (kΩ) is 2500 Ω? =
6. 6.🤖 if (temperature > 38) { show “Hot” } else if (temperature > 26) { show “Warm” } else { show “Cool” }
   The temperature is 16 °C. What is shown? (a) Cool (b) Hot (c) Warm
7. 7.Which of these has no microcontroller inside? (a) a bicycle bell (b) a washing machine (c) a digital alarm clock (d) a digital thermometer
8. 8.✏️ In a circuit diagram, which part is drawn as a small empty box? (a) cell (b) battery (c) resistor (d) switch
9. 9.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
10. 10.Which of these is safe? (a) touch a fallen wire (b) take cells out after use (c) open a phone charger (d) poke things in a socket
11. 11.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V ÷ I (d) P = V × I
12. 12.🧮 Five equal 25 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
13. 13.True or false: a steel spoon is an insulator. (a) True (b) False
14. 14.Which of these saves electricity? (a) iron one shirt at a time (b) leave fridge door open (c) switch off empty rooms (d) run fans in empty rooms
15. 15.⚠️ Is it safe to use small battery cells? (a) safe (b) not safe
16. 16.🔺 A current of 50 mA flows when 16.5 V is joined across a resistor. What is its resistance (in ohms)?
17. 17.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
18. 18.✏️ In a circuit diagram, wires are usually drawn as … (a) dotted circles (b) straight lines (c) little stars (d) wavy lines
19. 19.⚡ A 1.2 W device works on 12 V. What current does it take (in amperes)? =
20. 20.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) False (b) True
21. 21.🔦 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 rubber eraser. Does the bulb glow? (a) No (b) Yes
22. 22.🔁 count = 1
    repeat 5 times { count = count + 4 }
    What is count at the end?
23. 23.Which of these is true of a parallel circuit? (a) bulbs share the voltage (b) a break stops every bulb (c) own switch for each bulb (d) one bulb out, all go out
24. 24.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) zero (c) stay the same (d) smaller
25. 25.🔌 Is a dry cork a conductor or an insulator? (a) an insulator (b) a conductor
26. 26.🔘 Which kind of switch slides side to side? (a) a push button (b) a tilt switch (c) a toggle switch (d) a slide switch
27. 27.True or false: to switch off empty rooms saves electricity. (a) True (b) False
28. 28.Which drawing is the symbol for a voltmeter? (a) a circle with V inside (b) a long and a short line (c) a dot where wires meet (d) a circle with an X in it
29. 29.🤖 if (sound > 80) { red LED ON } else { green LED ON }
    The sound sensor reads 69. What happens? (a) red LED ON (b) green LED ON
30. 30.Which drawing is the symbol for a cell? (a) a dot where wires meet (b) a circle with a cross (c) one tall, one short bar (d) a small empty box
31. 31.🤖 if (temperature > 28) { fan ON } else { fan OFF }
    The temperature sensor reads 24 °C. What happens? (a) fan OFF (b) fan ON
32. 32.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
33. 33.True or false: “used in house wiring” is true of a parallel circuit. (a) False (b) True
34. 34.🌈 A resistor has the colour bands red, blue, red. What is its value in kilo-ohms (kΩ)? =
35. 35.🔋 Does a computer give electricity or use electricity? (a) gives electricity (b) uses electricity
36. 36.Which drawing is the symbol for a resistor? (a) two equal parallel lines (b) one tall, one short bar (c) a plain rectangle (d) a circle with M inside
37. 37.✏️ 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
38. 38.🤖 What is a microcontroller? (a) a computer on one chip (b) a big desktop computer (c) a kind of bulb (d) a type of battery
39. 39.🧩 Which component makes a beeping sound? (a) capacitor (b) buzzer (c) potentiometer (d) fuse
40. 40.🔺 A current of 0.2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =

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