Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 970 · 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.True or false: a laptop needs much more power. (a) False (b) True
2. 2.⚡ Which formula gives electric power? (a) P = V + I (b) P = I ÷ V (c) P = V ÷ I (d) P = V × I
3. 3.Which of these is true of a series circuit? (a) used in house wiring (b) each gets the full volts (c) a break stops every bulb (d) one out, the rest glow
4. 4.⚡ A bicycle dynamo changes which kind of energy into electricity? (a) movement energy (b) light energy (c) sound energy (d) chemical energy
5. 5.🔍 A distance sensor sends a sound pulse and hears the echo 4 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
6. 6.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
7. 7.⚡ What do we call a flow of electric charge through a wire? (a) sound (b) a magnet (c) friction (d) electric current
8. 8.📶 A pin set LOW gives about … (a) 9 V (b) 5 V (c) 1.5 V (d) 0 V
9. 9.Which of these is true of a parallel circuit? (a) one bulb out, all go out (b) a single current path (c) a break stops every bulb (d) each gets the full volts
10. 10.True or false: a toy robot usually has a microcontroller inside. (a) False (b) True
11. 11.📏 In the water-pipe picture of a circuit, current is like … (a) the water pressure (b) a narrow pipe (c) the pipe colour (d) the flow of water
12. 12.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 7 HIGH
    set pin 8 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF
13. 13.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 4 V supply. What current flows (in mA)?
14. 14.💡 Why does an LED need a resistor in series? (a) to limit the current (b) to change its colour (c) to store charge (d) to make it brighter
15. 15.Which job needs a sound sensor? (a) make a parking alarm (b) measure classroom noise (c) start a fan when hot (d) water a dry plant
16. 16.True or false: to keep drinks far away is safe. (a) False (b) True
17. 17.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V + R (c) I = V ÷ R (d) I = V × R
18. 18.🔐 Is it a good or a risky habit to log out of shared phones? (a) good habit (b) risky habit
19. 19.⚡ A 1.8 W device works on 9 V. What current does it take (in amperes)? =
20. 20.True or false: on an LED, the round-side leg is the cathode (−). (a) False (b) True
21. 21.⚡ A 24 W device works on 24 V. What current does it take (in amperes)? =
22. 22.Which of these is true of a parallel circuit? (a) a break stops every bulb (b) one bulb out, all go out (c) a single current path (d) one out, the rest glow
23. 23.💡 An LED is joined to a 3 V battery through a 220 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) lights up (b) does not light (c) may burn out
24. 24.True or false: “one out, the rest glow” is true of a series circuit. (a) False (b) True
25. 25.Which drawing is the symbol for a battery? (a) many long-short pairs (b) a circle with a cross (c) one tall, one short bar (d) two equal parallel lines
26. 26.🔁 count = 3
    while (count < 27) { count = count + 3 }
    How many times does the loop run?
27. 27.True or false: a laptop uses very little power. (a) False (b) True
28. 28.True or false: an LED is a resistance knob. (a) True (b) False
29. 29.🔢 To get a sensor reading onto a phone, which comes first: “the cloud stores it” or “the app shows it”? (a) the cloud stores it (b) the app shows it
30. 30.🔗 Series or parallel circuit: “one out, the rest glow”? (a) series (b) parallel
31. 31.⏱️ How many milliseconds is a wait of 4.1 seconds?
32. 32.⚡ Power tells us … (a) the colour of light (b) the length of a wire (c) energy used each second (d) the size of a cell
33. 33.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
34. 34.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they explode (b) they keep glowing (c) they get dimmer (d) they all go out
35. 35.Which job needs a light sensor? (a) water a dry plant (b) switch on with a clap (c) open blinds at sunrise (d) make a parking alarm
36. 36.🌈 Which band is read first on a resistor? (a) the gold band (b) any band (c) the one nearest an end (d) the widest gap
37. 37.📏 In the water-pipe picture of a circuit, voltage is like … (a) the tap handle (b) the pipe colour (c) the water tank lid (d) the water pressure
38. 38.True or false: a ceramic cup is a conductor. (a) True (b) False
39. 39.🤖 if (temperature > 30) { fan ON } else { fan OFF }
    The temperature sensor reads 25 °C. What happens? (a) fan ON (b) fan OFF
40. 40.🔢 To run one loop of a plant-watering program, which comes first: “compare with the limit” or “wait a few seconds”? (a) wait a few seconds (b) compare with the limit

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