Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 134 · 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 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
2. 2.🧮 Two equal 10 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
3. 3.🔐 Is it a good or a risky habit to set up with a parent? (a) risky habit (b) good habit
4. 4.💡 5 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 5 is taken out of its holder. Does bulb 1 glow? (a) No (b) Yes
5. 5.Which of these means the circuit is closed? (a) the loop is complete (b) the switch is OFF (c) a wire is cut (d) the bulb is unscrewed
6. 6.🔘 A cell and a bulb are joined to two side-by-side paths: path 1 has switches A and B one after another, path 2 has switch C. A is OFF, B is ON and C is OFF. Does the bulb glow? (a) Yes (b) No
7. 7.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
   set pin 7 LOW
   set pin 8 LOW
   set pin 8 LOW
   set pin 7 HIGH
   set pin 8 LOW
   Is the LED ON or OFF at the end? (a) ON (b) OFF
8. 8.Which of these is not safe? (a) use small battery cells (b) keep drinks far away (c) build with an adult near (d) use mains for a project
9. 9.🔐 Is it a good or a risky habit to share camera links? (a) good habit (b) risky habit
10. 10.🌐 Each reading a sensor sends is 50 bytes. How many bytes do 140 readings take?
11. 11.Which of these is not an IoT device? (a) an app-controlled bulb (b) a wind-up clock (c) a smart energy meter (d) a Wi-Fi smart plug
12. 12.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 kilowatt-hour (kWh) (c) 1 volt (d) 1 watt
13. 13.⚡ A 0.75 W device works on 3 V. What current does it take (in amperes)? =
14. 14.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they get dimmer (b) they all go out (c) they explode (d) they keep glowing
15. 15.True or false: to tap unknown app links is a good habit. (a) True (b) False
16. 16.True or false: on a cell, “the flat end” means the − (negative) end. (a) True (b) False
17. 17.What does an LDR do? (a) beeps for an alarm (b) limits the current (c) turns a fan or wheels (d) senses how bright it is
18. 18.🧮 A 330 Ω resistor is joined in series with two equal 100 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
19. 19.🔗 Series or parallel circuit: “a single current path”? (a) series (b) parallel
20. 20.True or false: a spinning top usually has a microcontroller inside. (a) False (b) True
21. 21.✏️ In a circuit diagram, wires are usually drawn as … (a) dotted circles (b) little stars (c) wavy lines (d) straight lines
22. 22.Which of these is not an IoT device? (a) a fitness band with app (b) an app-controlled bulb (c) a Wi-Fi weather station (d) a plain table fan
23. 23.🔋 5 identical 2 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
24. 24.Which of these is a good habit? (a) ignore update messages (b) cover unused cameras (c) post your live location (d) accept every permission
25. 25.🔋 5 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)? =
26. 26.⚡ A fan changes electrical energy mainly into which kind of energy? (a) chemical energy (b) light energy (c) sound energy (d) movement energy
27. 27.🤖 if (temperature > 33) { show “Hot” } else if (temperature > 23) { show “Warm” } else { show “Cool” }
    The temperature is 12 °C. What is shown? (a) Cool (b) Hot (c) Warm
28. 28.🔺 A current of 3 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
29. 29.🔗 Series or parallel circuit: “one bulb out, all go out”? (a) parallel (b) series
30. 30.⏱️ A program says “wait 3750 ms”. How many seconds is that? =
31. 31.🔐 Is it a good or a risky habit to cover unused cameras? (a) risky habit (b) good habit
32. 32.💡 4 identical bulbs are joined in parallel (each on its own side-by-side path) with a battery and a closed switch on the main wire. Bulb 2 is taken out of its holder. Does bulb 1 glow? (a) Yes (b) No
33. 33.🔍 Which is the odd one out? (a) a smart energy meter (b) a plain wall switch (c) a fitness band with app (d) an app-controlled bulb
34. 34.🔺 A current of 10 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
35. 35.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a paper strip across the gap. Does the bulb glow? (a) Yes (b) No
36. 36.✏️ In a cell symbol, which line is the + terminal? (a) both lines (b) the longer line (c) neither line (d) the shorter line
37. 37.🔢 To run one loop of a plant-watering program, which is the FIRST step? (a) compare with the limit (b) wait a few seconds (c) switch the pump on/off (d) read the soil sensor
38. 38.🧮 Two equal 50 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
39. 39.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a cotton thread across the gap. Does the bulb glow? (a) Yes (b) No
40. 40.🔺 A current of 0.2 A flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?

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