Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 454 · 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.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
   set pin 7 LOW
   set pin 7 LOW
   set pin 8 LOW
   set pin 8 LOW
   Is the LED ON or OFF at the end? (a) OFF (b) ON
2. 2.Which of these is an IoT device? (a) a smart energy meter (b) a paper calendar (c) a wind-up clock (d) a plain wall switch
3. 3.Which of these is true of a parallel circuit? (a) a single current path (b) each gets the full volts (c) one bulb out, all go out (d) bulbs share the voltage
4. 4.True or false: the voltmeter measures current. (a) True (b) False
5. 5.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. Does the bulb glow? (a) Yes (b) No
6. 6.⏱️ repeat 3 times { buzzer ON; wait 800 ms; buzzer OFF; wait 800 ms }
   How many milliseconds does this take in all?
7. 7.True or false: a ceramic cup is a conductor. (a) True (b) False
8. 8.🧩 Which part changes electrical energy into movement? (a) a resistor (b) a motor (c) an LED (d) a fuse
9. 9.🔁 What does “count = count + 1” do? (a) sets count to 1 (b) adds 1 to count (c) prints 1 (d) takes 1 away
10. 10.Which of these means the circuit is closed? (a) the switch is OFF (b) all wires are joined (c) a cell is taken out (d) a wire is cut
11. 11.⏱️ loop forever { LED ON; wait 950 ms; LED OFF; wait 550 ms }
    How many milliseconds does one blink (ON + OFF) take?
12. 12.🤖 “if (A AND B)” is true when … (a) only B is true (b) both A and B are true (c) both are false (d) only A is true
13. 13.True or false: a push button works only while pressed. (a) True (b) False
14. 14.True or false: to climb an electric pole is safe. (a) True (b) False
15. 15.🔘 What does a switch do in a circuit? (a) changes the voltage (b) makes electricity (c) opens or closes the loop (d) stores current
16. 16.True or false: a laptop runs many apps at once. (a) True (b) False
17. 17.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 21 Ω resistor? (a) orange-brown-black (b) brown-red-black (c) red-brown-black (d) red-brown-brown
18. 18.🔁 total = 0
    for i = 1 to 4 { total = total + i }
    What is total at the end?
19. 19.Which job is done by the voltage regulator? (a) brings power and code (b) keeps the voltage steady (c) runs the program (d) restarts the program
20. 20.🔁 What does a variable do in a program? (a) blinks an LED (b) joins two wires (c) measures light (d) stores a value
21. 21.🔐 A smart-camera app asks for your school name and home address. What should you do? (a) share it with friends (b) post it online (c) ask a parent first (d) type it all in
22. 22.💡 6 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 6 is taken out of its holder. How many bulbs glow?
23. 23.🔺 A 12.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
24. 24.⚙️ Which actuator would you use to move water to plants? (a) a display (b) an LED (c) a pump (d) a servo motor
25. 25.True or false: on a cell, “usually the black wire” means the − (negative) end. (a) True (b) False
26. 26.🔐 Is it a good or a risky habit to reuse one password? (a) risky habit (b) good habit
27. 27.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 7 LOW
    set pin 8 LOW
    set pin 8 LOW
    set pin 8 LOW
    Is the LED ON or OFF at the end? (a) OFF (b) ON
28. 28.What does a reed switch do? (a) springs back when let go (b) slides side to side (c) flips up or down (d) closes near a magnet
29. 29.💡 A battery lights 4 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) the same (b) dimmer (c) brighter
30. 30.🤖 Where does the board keep its program when the power is off? (a) the power LED (b) the resistor (c) the USB cable (d) flash memory
31. 31.🔐 Is it a good or a risky habit to cover unused cameras? (a) risky habit (b) good habit
32. 32.Which of these means the circuit is open? (a) the switch is ON (b) the bulb is unscrewed (c) all wires are joined (d) the loop is complete
33. 33.🔁 count = 5
    while (count < 21) { count = count + 2 }
    How many times does the loop run?
34. 34.🔋 3 identical 3 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
35. 35.True or false: a resistor limits the current. (a) False (b) True
36. 36.✏️ In a circuit diagram, which part is drawn as a line lifted at a gap? (a) wire (b) switch (c) ammeter (d) motor
37. 37.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
38. 38.🤖 if (moisture < 50) { pump ON } else { pump OFF }
    The soil moisture sensor reads 59 %. What happens? (a) pump ON (b) pump OFF
39. 39.🔦 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) No (b) Yes
40. 40.📶 Digital or analog: the room temperature? (a) analog (b) digital

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