Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 165 · 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.🤖 if (temperature > 38) { show “Hot” } else if (temperature > 20) { show “Warm” } else { show “Cool” }
   The temperature is 18 °C. What is shown? (a) Cool (b) Hot (c) Warm
2. 2.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) not joined (b) in parallel (c) in series (d) by Wi-Fi
3. 3.🔍 Which sensor would you use to warn of a gas leak? (a) a gas sensor (b) a soil moisture sensor (c) a distance sensor (d) a light sensor
4. 4.🔁 count = 4
   while (count < 19) { count = count + 5 }
   How many times does the loop run?
5. 5.⚡ A device works on 3 V and takes 0.1 A. What is its power (in watts)? =
6. 6.✏️ In a circuit diagram, wires are usually drawn as … (a) straight lines (b) wavy lines (c) little stars (d) dotted circles
7. 7.🔋 6 identical 1.2 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
8. 8.⚡ What does a rice cooker mainly change electricity into? (a) movement (b) light (c) heat (d) sound
9. 9.🔐 Privacy for a smart device means controlling … (a) who can see your data (b) its battery size (c) its colour (d) how loud it beeps
10. 10.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 30 Ω resistor? (a) orange-black-black (b) yellow-orange-black (c) yellow-black-black (d) orange-black-brown
11. 11.🧮 A 3.5 V battery is joined to 2 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
12. 12.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) only one (c) none (d) both of them
13. 13.🧩 A capacitor in a circuit can … (a) measure heat (b) make light (c) store charge briefly (d) spin a wheel
14. 14.True or false: a laptop runs many apps at once. (a) False (b) True
15. 15.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to make it brighter (c) to limit the current (d) to store charge
16. 16.🔁 x = 2
    repeat 1 time { x = x × 2 }
    What is x at the end?
17. 17.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a steel spoon across the gap. Does the bulb glow? (a) No (b) Yes
18. 18.Which of these is the output? (a) compare with a limit (b) check if temp > 30 (c) a light level reading (d) the fan starts
19. 19.True or false: on a cell, “the end with a bump” means the + (positive) end. (a) False (b) True
20. 20.🔍 Which is the odd one out? (a) a turning knob (b) a motion sensor (c) a sound sensor (d) a water pump
21. 21.🌈 In the resistor colour code, which number does yellow stand for?
22. 22.True or false: a spinning top has no microcontroller inside. (a) False (b) True
23. 23.💡 3 identical bulbs are joined in parallel across a 9 V battery (ideal wires). How many volts does each bulb get? =
24. 24.🔢 To get a sensor reading onto a phone, which comes first: “it is sent by Wi-Fi” or “the sensor measures”? (a) it is sent by Wi-Fi (b) the sensor measures
25. 25.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
26. 26.🔁 count = 1
    repeat 4 times { count = count + 7 }
    What is count at the end?
27. 27.🔋 On a cell, does “the flat end” mean the + end or the − end? (a) − (negative) (b) + (positive)
28. 28.True or false: resistance is measured in ohms (Ω). (a) True (b) False
29. 29.💡 An LED is joined to a 6 V battery with no resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) lights up (b) may burn out (c) does not light
30. 30.🔌 Which metal is used for most electric wires at home? (a) glass (b) copper (c) rubber (d) plastic
31. 31.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) OFF (b) ON
32. 32.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
33. 33.Which of these is a conductor? (a) a woollen thread (b) a wooden stick (c) a dry cork (d) an iron nail
34. 34.💡 Why is house wiring done in parallel? (a) so all go off together (b) each gets full voltage (c) to make bulbs dim (d) to save copper only
35. 35.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the glass (d) the filament
36. 36.True or false: “one bulb out, all go out” is true of a parallel circuit. (a) False (b) True
37. 37.Which of these is a conductor? (a) a rubber eraser (b) a plastic straw (c) a brass key (d) a cotton thread
38. 38.⚡ Which formula gives electric power? (a) P = V × I (b) P = V ÷ I (c) P = I ÷ V (d) P = V + I
39. 39.🔍 Which sensor would you use to switch on lamps at dusk? (a) a distance sensor (b) a gas sensor (c) a motion sensor (d) a light sensor
40. 40.🌈 A resistor has the colour bands orange, blue, brown. What is its value (in ohms)?

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