Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 367 · 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.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
2. 2.True or false: a buzzer lets current go one way. (a) True (b) False
3. 3.🤖 if (moisture < 50) { pump ON } else { pump OFF }
   The soil moisture sensor reads 65 %. What happens? (a) pump ON (b) pump OFF
4. 4.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
   set pin 7 LOW
   set pin 8 LOW
   set pin 8 HIGH
   Is the LED ON or OFF at the end? (a) OFF (b) ON
5. 5.🔘 Which kind of switch stays where you flip it? (a) a tilt switch (b) a toggle switch (c) a slide switch (d) a reed switch
6. 6.Which of these is true of a series circuit? (a) each gets the full volts (b) own switch for each bulb (c) one bulb out, all go out (d) one out, the rest glow
7. 7.🔦 A circuit has a used-up (dead) 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
8. 8.🔌 Is a water pump an input or an output for a microcontroller? (a) input (b) output
9. 9.✏️ Why do engineers draw circuits with symbols? (a) to make it colourful (b) to hide the circuit (c) symbols are heavier (d) quick and clear for all
10. 10.🌐 Each reading a sensor sends is 20 bytes. How many bytes do 90 readings take?
11. 11.⚡ A device works on 9 V and takes 0.2 A. What is its power (in watts)? =
12. 12.Which of these is a conductor? (a) aluminium foil (b) a plastic ruler (c) a rubber eraser (d) a ceramic cup
13. 13.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put an iron nail across the gap. Does the bulb glow? (a) No (b) Yes
14. 14.What does a buzzer do? (a) limits the current (b) makes things spin (c) has coloured bands (d) makes a beeping sound
15. 15.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
16. 16.🔺 A current of 25 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
17. 17.🔦 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
18. 18.Which of these is a conductor? (a) a wooden stick (b) a woollen thread (c) a rubber band (d) a metal paper clip
19. 19.⚠️ Why must we never touch switches with wet hands? (a) it is just untidy (b) water makes it cold (c) it spoils the paint (d) water carries current
20. 20.Which job needs a display? (a) move water to plants (b) turn to an exact angle (c) open a gate to 90° (d) show the temperature
21. 21.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V + I (d) P = V × I
22. 22.True or false: a ceramic cup is a conductor. (a) False (b) True
23. 23.🌐 Each reading a sensor sends is 20 bytes. How many bytes do 50 readings take?
24. 24.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
25. 25.💡 A red LED uses 2 V and should get 20 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
26. 26.🔁 count = 0
    while (count < 12) { count = count + 2 }
    How many times does the loop run?
27. 27.True or false: a rice cooker mainly gives out light. (a) False (b) True
28. 28.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) both parts (b) the else part (c) the if part (d) neither part
29. 29.🔦 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 safety pin. Does the bulb glow? (a) Yes (b) No
30. 30.🤖 Microcontroller or laptop: which one has no screen of its own? (a) laptop (b) microcontroller
31. 31.🔐 Is it a good or a risky habit to turn off unused gadgets? (a) good habit (b) risky habit
32. 32.⏱️ loop forever { LED ON; wait 500 ms; LED OFF; wait 200 ms }
    How many milliseconds does one blink (ON + OFF) take?
33. 33.⚡ Which tiny particles drift along a metal wire to carry the current? (a) water drops (b) dust particles (c) photons (d) electrons
34. 34.🤖 if (temperature > 28) { fan ON } else { fan OFF }
    The temperature sensor reads 33 °C. What happens? (a) fan OFF (b) fan ON
35. 35.✏️ In a circuit diagram, which part is drawn as a circle with a cross? (a) battery (b) wire (c) bulb (d) motor
36. 36.True or false: “a break stops every bulb” is true of a series circuit. (a) False (b) True
37. 37.💡 An LED is joined to a 5 V battery through a 220 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) may burn out (b) does not light (c) lights up
38. 38.🔺 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
39. 39.🔋 What is a battery? (a) a switch with a lid (b) one single wire (c) a kind of bulb (d) two or more cells joined
40. 40.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the glass (d) the filament

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