Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 186 · 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.✏️ In a circuit diagram, wires are usually drawn as … (a) wavy lines (b) straight lines (c) dotted circles (d) little stars
2. 2.True or false: to measure classroom noise, use a soil moisture sensor. (a) True (b) False
3. 3.🌐 Is a Wi-Fi weather station an IoT device? (a) not an IoT device (b) an IoT device
4. 4.🔋 6 identical 1.5 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
5. 5.💡 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
   Is the LED ON or OFF at the end? (a) OFF (b) ON
6. 6.🧮 Two equal 470 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
7. 7.🔁 What does “count = count + 1” do? (a) takes 1 away (b) sets count to 1 (c) prints 1 (d) adds 1 to count
8. 8.Which of these is true of a parallel circuit? (a) one bulb out, all go out (b) a break stops every bulb (c) own switch for each bulb (d) bulbs share the voltage
9. 9.⚠️ Is it safe to touch a fallen wire? (a) not safe (b) safe
10. 10.🔘 Which kind of switch springs back when let go? (a) a reed switch (b) a toggle switch (c) a push button (d) a tilt switch
11. 11.⏱️ How many milliseconds is a wait of 3 seconds?
12. 12.🔍 Which is the odd one out? (a) a siren (b) a buzzer (c) a school bell (d) a street light
13. 13.🌐 In an IoT system, which part acts on a command? (a) actuator (b) phone app (c) microcontroller (d) sensor
14. 14.True or false: a dot where wires meet is the symbol for a junction. (a) False (b) True
15. 15.True or false: an LED lamp mainly gives out light. (a) False (b) True
16. 16.✏️ Why do engineers draw circuits with symbols? (a) to make it colourful (b) to hide the circuit (c) symbols are heavier (d) quick and clear for all
17. 17.⚡ A 0.75 W device works on 1.5 V. What current does it take (in amperes)? =
18. 18.⚡ A 6 W device works on 3 V. What current does it take (in amperes)? =
19. 19.📏 How many milliamperes (mA) make 1 ampere? (a) 60 (b) 100 (c) 10 (d) 1000
20. 20.Which of these is true of a series circuit? (a) a single current path (b) one out, the rest glow (c) own switch for each bulb (d) many paths for current
21. 21.True or false: a microcontroller has a built-in keyboard. (a) True (b) False
22. 22.📏 How many milliamperes (mA) is 2.47 A?
23. 23.🔍 Which is the odd one out? (a) leave fridge door open (b) use old filament bulbs (c) run fans in empty rooms (d) close the fridge quickly
24. 24.True or false: to make a parking alarm, use a distance sensor. (a) False (b) True
25. 25.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
26. 26.🌈 In the resistor colour code, which number does grey stand for?
27. 27.Which of these is a conductor? (a) a plastic straw (b) a cotton thread (c) a rubber band (d) a safety pin
28. 28.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a resistor (c) a diode (d) a buzzer
29. 29.🤖 if (sound > 60) { red LED ON } else { green LED ON }
    The sound sensor reads 60. What happens? (a) red LED ON (b) green LED ON
30. 30.🔺 A current of 2 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
31. 31.True or false: a cotton thread is an insulator. (a) False (b) True
32. 32.Which of these means the circuit is closed? (a) a wire has come loose (b) all wires are joined (c) the bulb is unscrewed (d) a wire is cut
33. 33.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 kilowatt-hour (kWh) (c) 1 volt (d) 1 ampere
34. 34.True or false: to start a fan when hot, use a distance sensor. (a) True (b) False
35. 35.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
36. 36.🔺 A current of 1 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
37. 37.🤖 if (light < 400 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 600 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
38. 38.🔺 A 16 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
39. 39.⚠️ Why must we never touch switches with wet hands? (a) it spoils the paint (b) it is just untidy (c) water makes it cold (d) water carries current
40. 40.⏱️ How many milliseconds are in 1 second? (a) 10 (b) 1000 (c) 100 (d) 60

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