Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 39 · 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 job needs an LED? (a) show the temperature (b) move water to plants (c) show a status light (d) beep an alarm
2. 2.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
3. 3.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 600 ms }
   How many milliseconds does one blink (ON + OFF) take?
4. 4.⏱️ How many milliseconds is a wait of 0.7 seconds?
5. 5.⚙️ Which actuator would you use to beep an alarm? (a) a servo motor (b) a pump (c) a display (d) a buzzer
6. 6.Which of these means the circuit is open? (a) the bulb is unscrewed (b) all wires are joined (c) the switch is ON (d) the loop is complete
7. 7.🔋 A 9 V battery and three 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
8. 8.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
9. 9.Which job needs a servo motor? (a) spin a robot’s wheels (b) beep an alarm (c) show a status light (d) turn to an exact angle
10. 10.Which of these is the input? (a) check if temp > 30 (b) a buzzer beeps (c) a button press (d) decide if soil is dry
11. 11.True or false: on a cell, “usually the red wire” means the + (positive) end. (a) False (b) True
12. 12.⚠️ Is it safe to dry your hands first? (a) not safe (b) safe
13. 13.🔁 count = 8
    repeat 4 times { count = count + 5 }
    What is count at the end?
14. 14.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
15. 15.True or false: “used in house wiring” is true of a parallel circuit. (a) False (b) True
16. 16.🔋 4 identical 1.2 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
17. 17.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I + R (c) V = I × R (d) V = I ÷ R
18. 18.⏱️ loop forever { LED ON; wait 200 ms; LED OFF; wait 50 ms }
    How many times does the LED blink in 3 seconds?
19. 19.⚡ A device works on 1.5 V and takes 2 A. What is its power (in watts)? =
20. 20.🔍 Which is the odd one out? (a) a loudspeaker (b) a doorbell (c) a buzzer (d) a water heater
21. 21.🔍 Which is the odd one out? (a) accept every permission (b) share camera links (c) ignore update messages (d) set a strong password
22. 22.What does a potentiometer do? (a) has coloured bands (b) senses how hot it is (c) limits the current (d) is a resistance knob
23. 23.🔁 x = 1
    repeat 2 times { x = x × 2 }
    What is x at the end?
24. 24.🔺 A 12 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
25. 25.⏱️ repeat 5 times { buzzer ON; wait 200 ms; buzzer OFF; wait 300 ms }
    How many milliseconds does this take in all?
26. 26.🌐 Is a Wi-Fi weather station an IoT device? (a) not an IoT device (b) an IoT device
27. 27.🔋 On a cell, does “usually the black wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
28. 28.What does a motor do? (a) senses how bright it is (b) glows using little power (c) turns a fan or wheels (d) lets current go one way
29. 29.Which of these gives us electricity? (a) a computer (b) a solar panel (c) an air conditioner (d) a television
30. 30.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 350 ms }
    How many times does the LED blink in 5 seconds?
31. 31.True or false: “a motion sensor signal” is the input. (a) True (b) False
32. 32.⚠️ Is it safe to poke things in a socket? (a) safe (b) not safe
33. 33.🔋 A 6 V battery and three 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
34. 34.🧮 A 2.25 V battery is joined to 4 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
35. 35.⏱️ repeat 4 times { buzzer ON; wait 1000 ms; buzzer OFF; wait 500 ms }
    How many milliseconds does this take in all?
36. 36.What does a thermistor do? (a) makes a beeping sound (b) smooths a wobbly supply (c) lets current go one way (d) senses how hot it is
37. 37.True or false: a table fan mainly makes movement. (a) True (b) False
38. 38.⚡ What does a street light mainly change electricity into? (a) sound (b) heat (c) light (d) movement
39. 39.🔐 Is it a good or a risky habit to accept every permission? (a) good habit (b) risky habit
40. 40.📶 A pin that reads a push button is set as … (a) a resistor (b) an input (c) an output (d) a battery

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