Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 914 · 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.⚡ Power tells us … (a) the size of a cell (b) energy used each second (c) the colour of light (d) the length of a wire
2. 2.🔍 Which is the odd one out? (a) reuse one password (b) set a strong password (c) share camera links (d) keep factory passwords
3. 3.True or false: a push button works only while pressed. (a) False (b) True
4. 4.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the if part (b) the else part (c) neither part (d) both parts
5. 5.🔺 A 3.75 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
6. 6.Which of these saves electricity? (a) use LED lamps (b) run fans in empty rooms (c) leave fridge door open (d) leave the TV on standby
7. 7.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) becomes zero (c) gets bigger (d) stays the same
8. 8.🌈 In the resistor colour code, which number does brown stand for?
9. 9.🔁 repeat 6 times { repeat 5 times { beep } }
   How many beeps are there?
10. 10.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
11. 11.⚡ A 2.5 W device works on 5 V. What current does it take (in amperes)? =
12. 12.🌐 What does IoT stand for? (a) Input of Tools (b) Internet of Talk (c) Internet of Things (d) Inside of Toys
13. 13.🔘 Two switches are in series. When does the bulb glow? (a) when either is ON (b) when both are OFF (c) when both are ON (d) never
14. 14.🔺 A current of 10 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
15. 15.🔍 Which sensor would you use to switch on lamps at dusk? (a) a motion sensor (b) a distance sensor (c) a light sensor (d) a gas sensor
16. 16.💡 A red LED uses 2 V and should get 10 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
17. 17.🔗 Series or parallel circuit: “a break stops every bulb”? (a) series (b) parallel
18. 18.💡 A red LED uses 2 V and should get 25 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
19. 19.🌐 How does a home IoT device usually send its data to the app? (a) through a candle (b) by post (c) by shouting (d) over Wi-Fi
20. 20.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) stay the same (c) zero (d) smaller
21. 21.💡 A battery lights 4 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) dimmer (b) the same (c) brighter
22. 22.🔗 Series or parallel circuit: “a single current path”? (a) parallel (b) series
23. 23.🧮 A 6 V battery is joined to 3 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
24. 24.⏱️ How many milliseconds is a wait of 0.4 seconds?
25. 25.🤖 Does a digital alarm clock usually have a microcontroller inside? (a) No (b) Yes
26. 26.💡 A battery lights 5 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) brighter (b) dimmer (c) the same
27. 27.⏱️ What does “wait 500 ms” do? (a) waits 500 seconds (b) pauses for half a second (c) blinks 500 times (d) turns the LED off
28. 28.📶 How many states can a digital pin have? (a) one (b) ten (c) a thousand (d) two
29. 29.True or false: “one bulb out, all go out” is true of a parallel circuit. (a) True (b) False
30. 30.⚡ A device works on 3 V and takes 0.5 A. What is its power (in watts)? =
31. 31.True or false: to throw cells in a fire is not safe. (a) False (b) True
32. 32.🔋 2 identical 1.2 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
33. 33.🤖 if (moisture < 40) { pump ON } else { pump OFF }
    The soil moisture sensor reads 38 %. What happens? (a) pump ON (b) pump OFF
34. 34.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
35. 35.Which of these means the circuit is closed? (a) the switch is OFF (b) all wires are joined (c) a wire has come loose (d) the bulb is unscrewed
36. 36.🔍 Which sensor would you use to keep an incubator warm? (a) a temperature sensor (b) a rain sensor (c) a gas sensor (d) a distance sensor
37. 37.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 10 hours. How many watt-hours (Wh) are saved?
38. 38.🔌 Which part of a screwdriver should an electrician hold? (a) the metal tip (b) the bare end (c) the plastic handle (d) the steel shaft
39. 39.🔢 To run one loop of a plant-watering program, which is the FIRST step? (a) read the soil sensor (b) compare with the limit (c) wait a few seconds (d) switch the pump on/off
40. 40.🌐 Is a smart energy meter an IoT device? (a) an IoT device (b) not an IoT device

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