Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 99 · 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.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) becomes zero (c) stays the same (d) gets smaller
2. 2.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 750 ms }
   How many milliseconds does one blink (ON + OFF) take?
3. 3.🧩 Which component smooths a wobbly supply? (a) capacitor (b) fuse (c) LED (d) motor
4. 4.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
5. 5.🧩 Which component senses how hot it is? (a) LED (b) LDR (c) buzzer (d) thermistor
6. 6.🔌 Why are electric wires covered in plastic? (a) plastic makes current (b) plastic is a conductor (c) plastic is an insulator (d) to make them heavy
7. 7.🤖 if (light < 400 AND motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 270 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON
8. 8.🔢 To run one loop of a plant-watering program, what comes right after “read the soil sensor”? (a) switch the pump on/off (b) compare with the limit (c) wait a few seconds
9. 9.🔘 Two switches are in parallel (side by side). When does the bulb glow? (a) when either is ON (b) only when both are ON (c) never (d) only when both are OFF
10. 10.🔗 Series or parallel circuit: “a break stops every bulb”? (a) parallel (b) series
11. 11.🔍 Which is the odd one out? (a) a Wi-Fi weather station (b) a Wi-Fi smart plug (c) a plain table fan (d) an app-controlled bulb
12. 12.🗺️ Before building a project, what should you write down first? (a) inputs and outputs (b) nothing at all (c) the final price (d) the box colour
13. 13.True or false: a thermistor glows using little power. (a) False (b) True
14. 14.🔺 A current of 0.25 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
15. 15.⚠️ Is it safe to touch a switch when wet? (a) safe (b) not safe
16. 16.🌈 In the resistor colour code, which number does grey stand for?
17. 17.🔁 count = 1
    while (count < 13) { count = count + 4 }
    How many times does the loop run?
18. 18.🔘 A bulb and a cell are joined through 3 switches one after another in a single loop (series). What is the smallest number of switches that must be ON to light the bulb?
19. 19.🔋 On a cell, does “the flat end” mean the + end or the − end? (a) + (positive) (b) − (negative)
20. 20.Which of these mainly makes movement? (a) a torch (b) a water heater (c) a ceiling fan (d) a tube light
21. 21.🌐 How does a home IoT device usually send its data to the app? (a) through a candle (b) by shouting (c) over Wi-Fi (d) by post
22. 22.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 5 hours. How many watt-hours (Wh) are saved?
23. 23.🧮 Resistors of 150 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
24. 24.⚡ What does a mixer grinder mainly change electricity into? (a) light (b) sound (c) movement (d) heat
25. 25.✏️ In a cell symbol, which line is the + terminal? (a) both lines (b) neither line (c) the shorter line (d) the longer line
26. 26.🧮 Resistors of 47 Ω, 22 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
27. 27.⚡ A 13.5 W device works on 9 V. What current does it take (in amperes)? =
28. 28.🤖 Does a hand pump usually have a microcontroller inside? (a) No (b) Yes
29. 29.⏱️ What does “wait 500 ms” do? (a) turns the LED off (b) pauses for half a second (c) blinks 500 times (d) waits 500 seconds
30. 30.True or false: to set up with a parent is a good habit. (a) True (b) False
31. 31.🔺 A current of 0.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
32. 32.🔁 repeat 4 times { repeat 2 times { beep } }
    How many beeps are there?
33. 33.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. A gap in one wire is bridged by a wooden stick. Does the bulb glow? (a) Yes (b) No
34. 34.Which of these is not safe? (a) build with an adult near (b) take cells out after use (c) use a cable with cuts (d) dry your hands first
35. 35.💡 5 identical bulbs are in parallel and each one takes 1.5 A. What total current (in amperes) comes from the battery? =
36. 36.🔐 Is it a good or a risky habit to install software updates? (a) risky habit (b) good habit
37. 37.🔺 A 1 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
38. 38.🤖 Does a smart watch usually have a microcontroller inside? (a) No (b) Yes
39. 39.✏️ Why do engineers draw circuits with symbols? (a) to hide the circuit (b) quick and clear for all (c) symbols are heavier (d) to make it colourful
40. 40.Which of these gives us electricity? (a) a refrigerator (b) a solar panel (c) a water pump (d) a computer

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