Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 295 · 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.🌈 A resistor has the colour bands violet, red, red. What is its value in kilo-ohms (kΩ)? =
2. 2.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 50 % (c) 25 % (d) 0 %
3. 3.Which of these wastes electricity? (a) close the fridge quickly (b) iron one shirt at a time (c) use LED lamps (d) set the AC to 24 °C
4. 4.🔺 A current of 20 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
5. 5.🔢 To run one loop of a plant-watering program, which is the FIRST step? (a) wait a few seconds (b) switch the pump on/off (c) compare with the limit (d) read the soil sensor
6. 6.🔺 A current of 1.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
7. 7.⚡ Which formula gives electric power? (a) P = V + I (b) P = V × I (c) P = V ÷ I (d) P = I ÷ V
8. 8.🔋 2 identical 3 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
9. 9.⚠️ Is it safe to use a cable with cuts? (a) not safe (b) safe
10. 10.🤖 Does a digital alarm clock usually have a microcontroller inside? (a) Yes (b) No
11. 11.🤖 if (distance < 15) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 21 cm. What happens? (a) buzzer is silent (b) buzzer beeps
12. 12.🔢 To plan an electronics project, what comes right after “draw the circuit diagram”? (a) list inputs and outputs (b) build it with an adult (c) pick a problem to solve (d) test it and fix it
13. 13.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) bigger (c) smaller (d) zero
14. 14.🏠 Which is a smart-home example? (a) a candle in a jar (b) a hand fan (c) lights on from an app (d) a printed map
15. 15.💡 What does LED stand for? (a) large electric dial (b) low energy device (c) light energy dial (d) light-emitting diode
16. 16.🔺 A current of 40 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
17. 17.🌐 Is a Wi-Fi smart plug an IoT device? (a) an IoT device (b) not an IoT device
18. 18.🔺 A current of 2.5 A flows when 30 V is joined across a resistor. What is its resistance (in ohms)?
19. 19.🤖 if (moisture < 30) { pump ON } else { pump OFF }
    The soil moisture sensor reads 16 %. What happens? (a) pump ON (b) pump OFF
20. 20.🔌 Is a woollen thread a conductor or an insulator? (a) a conductor (b) an insulator
21. 21.🔍 Which is the odd one out? (a) a steel spoon (b) a safety pin (c) a graphite rod (d) a woollen thread
22. 22.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 7 HIGH
    set pin 8 HIGH
    set pin 7 HIGH
    set pin 7 HIGH
    Is the LED ON or OFF at the end? (a) OFF (b) ON
23. 23.🔋 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)? =
24. 24.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a woollen thread across the gap. Does the bulb glow? (a) No (b) Yes
25. 25.🌈 A resistor has the colour bands brown, red, yellow. What is its value in kilo-ohms (kΩ)? =
26. 26.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) gets bigger (c) stays the same (d) becomes zero
27. 27.🔢 To plan an electronics project, which comes first: “build it with an adult” or “test it and fix it”? (a) build it with an adult (b) test it and fix it
28. 28.True or false: “decide if soil is dry” is the process. (a) True (b) False
29. 29.🔍 Which sensor would you use to water a dry plant? (a) a rain sensor (b) a distance sensor (c) a soil moisture sensor (d) a sound sensor
30. 30.🔁 repeat 4 times { repeat 3 times { beep } }
    How many beeps are there?
31. 31.🔺 A current of 0.1 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
32. 32.🤖 if (light < 400 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 550 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON
33. 33.True or false: a long and a short line is the symbol for a wire. (a) False (b) True
34. 34.True or false: a transistor stores a little charge. (a) False (b) True
35. 35.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
36. 36.🌈 A resistor has the colour bands green, green, red. What is its value in kilo-ohms (kΩ)? =
37. 37.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 8800 Ω resistor? (a) grey-grey-brown (b) grey-grey-orange (c) grey-grey-red (d) grey-white-red
38. 38.What does a slide switch do? (a) flips up or down (b) springs back when let go (c) stays where you flip it (d) slides side to side
39. 39.True or false: an electric drill mainly makes movement. (a) True (b) False
40. 40.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 100 ms }
    How many times does the LED blink in 8 seconds?

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