Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 245 · 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: to set the AC to 24 °C saves electricity. (a) False (b) True
2. 2.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
3. 3.🧮 Five equal 25 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
4. 4.🌈 In the resistor colour code, which number does orange stand for?
5. 5.📏 How many amperes (A) is 2780 mA? =
6. 6.🔍 Which sensor would you use to measure classroom noise? (a) a light sensor (b) a distance sensor (c) a motion sensor (d) a sound sensor
7. 7.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 100 (b) 10 (c) 1000 (d) 1024
8. 8.True or false: to dry your hands first is not safe. (a) True (b) False
9. 9.⚠️ A cell gets hot when its + and − ends are joined by a bare wire. What is this called? (a) an open circuit (b) a safe circuit (c) a short circuit (d) a parallel circuit
10. 10.🔺 A current of 10 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
11. 11.What does a tilt switch do? (a) works only while pressed (b) closes when tipped over (c) springs back when let go (d) closes near a magnet
12. 12.🤖 if (temperature > 30) { show “Hot” } else if (temperature > 23) { show “Warm” } else { show “Cool” }
    The temperature is 29 °C. What is shown? (a) Cool (b) Hot (c) Warm
13. 13.True or false: to read app permissions is a good habit. (a) False (b) True
14. 14.⏱️ loop forever { LED ON; wait 750 ms; LED OFF; wait 950 ms }
    How many milliseconds does one blink (ON + OFF) take?
15. 15.Which job is done by the reset button? (a) brings power and code (b) restarts the program (c) runs the program (d) shows the board is on
16. 16.What does a reed switch do? (a) closes when tipped over (b) closes near a magnet (c) flips up or down (d) springs back when let go
17. 17.🤖 if (temperature > 36) { show “Hot” } else if (temperature > 19) { show “Warm” } else { show “Cool” }
    The temperature is 14 °C. What is shown? (a) Hot (b) Warm (c) Cool
18. 18.⚠️ Is it safe to dry your hands first? (a) not safe (b) safe
19. 19.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 3.5 V supply. What current flows (in mA)?
20. 20.🤖 if (distance < 20) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 22 cm. What happens? (a) buzzer beeps (b) buzzer is silent
21. 21.🔺 A current of 2 A flows when 16 V is joined across a resistor. What is its resistance (in ohms)?
22. 22.Which job is done by the USB port? (a) brings power and code (b) keeps the voltage steady (c) connect sensors and LEDs (d) restarts the program
23. 23.🔍 Which sensor would you use to switch on with a clap? (a) a distance sensor (b) a temperature sensor (c) a sound sensor (d) a motion sensor
24. 24.🔁 repeat 4 times { repeat 5 times { beep } }
    How many beeps are there?
25. 25.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
26. 26.🔌 Most metals are good … (a) insulators (b) magnets only (c) conductors (d) batteries
27. 27.True or false: “a motion sensor signal” is the input. (a) True (b) False
28. 28.True or false: to use daylight to read wastes electricity. (a) True (b) False
29. 29.💡 2 identical bulbs are joined in parallel across a 12 V battery (ideal wires). How many volts does each bulb get? =
30. 30.🔌 Which metal is used for most electric wires at home? (a) copper (b) rubber (c) plastic (d) glass
31. 31.🔺 A current of 25 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
32. 32.🌐 Is an app-controlled bulb an IoT device? (a) an IoT device (b) not an IoT device
33. 33.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 4 V supply. What current flows (in mA)?
34. 34.📶 Digital or analog: the room temperature? (a) digital (b) analog
35. 35.⏱️ loop forever { LED ON; wait 200 ms; LED OFF; wait 300 ms }
    How many times does the LED blink in 8 seconds?
36. 36.🌐 In an IoT system, which part shows data to you? (a) microcontroller (b) phone app (c) cloud server (d) actuator
37. 37.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) bigger (c) zero (d) smaller
38. 38.💡 A battery lights 3 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
39. 39.Which of these is a good habit? (a) ignore update messages (b) tap unknown app links (c) turn off unused gadgets (d) keep factory passwords
40. 40.🧮 Three equal 150 Ω resistors are joined in parallel. What is the total resistance (in ohms)?

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