Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 458 · 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.🧩 Which component smooths a wobbly supply? (a) motor (b) capacitor (c) resistor (d) buzzer
2. 2.🔗 Series or parallel circuit: “one bulb out, all go out”? (a) series (b) parallel
3. 3.What does a reed switch do? (a) flips up or down (b) closes when tipped over (c) closes near a magnet (d) stays where you flip it
4. 4.🔍 Which is the odd one out? (a) a torch (b) a tube light (c) an electric toy car (d) a traffic signal
5. 5.🤖 “if (A AND B)” is true when … (a) only A is true (b) only B is true (c) both are false (d) both A and B are true
6. 6.Which of these gives us electricity? (a) a power station (b) a television (c) a mobile phone (d) an air conditioner
7. 7.Which of these mainly gives out light? (a) a street light (b) an electric iron (c) an electric kettle (d) an electric toy car
8. 8.⚡ What does a loudspeaker mainly change electricity into? (a) light (b) heat (c) sound (d) movement
9. 9.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) zero (c) bigger (d) smaller
10. 10.🌈 A resistor has the colour bands violet, red, red. What is its value (in ohms)?
11. 11.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the output (b) the battery (c) the input (d) the process
12. 12.🤖 if (light < 200 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 120 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
13. 13.📏 How many kilo-ohms (kΩ) is 1800 Ω? =
14. 14.⚠️ Which power source should children use for electronics projects? (a) a mains extension board (b) an inverter socket (c) a wall socket (d) a small battery pack
15. 15.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
16. 16.Which of these wastes electricity? (a) unplug idle chargers (b) set the AC to 24 °C (c) use LED lamps (d) use old filament bulbs
17. 17.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V × I (d) P = V + I
18. 18.🔺 A current of 2.5 A flows when 25 V is joined across a resistor. What is its resistance (in ohms)?
19. 19.Which job needs a temperature sensor? (a) keep an incubator warm (b) open blinds at sunrise (c) spot someone walking in (d) warn of a gas leak
20. 20.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
21. 21.🤖 Does a plain wall switch usually have a microcontroller inside? (a) Yes (b) No
22. 22.🔺 A 10 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
23. 23.🔺 A 6.6 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
24. 24.📶 Digital or analog: a button: pressed or not? (a) analog (b) digital
25. 25.💡 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
26. 26.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
27. 27.🧮 A 0.5 V battery is joined to 3 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
28. 28.🌈 Which band is read first on a resistor? (a) the widest gap (b) any band (c) the one nearest an end (d) the gold band
29. 29.⏱️ What does “wait 500 ms” do? (a) blinks 500 times (b) turns the LED off (c) pauses for half a second (d) waits 500 seconds
30. 30.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
31. 31.True or false: a doorbell mainly gives out light. (a) True (b) False
32. 32.🔢 To plan an electronics project, which is the LAST step? (a) draw the circuit diagram (b) pick a problem to solve (c) list inputs and outputs (d) test it and fix it
33. 33.✏️ In a cell symbol, which line is the + terminal? (a) the shorter line (b) both lines (c) neither line (d) the longer line
34. 34.🧩 Which component beeps for an alarm? (a) fuse (b) thermistor (c) buzzer (d) LDR
35. 35.🔺 A current of 2.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
36. 36.💡 3 identical bulbs are joined in parallel across a 12 V battery (ideal wires). How many volts does each bulb get? =
37. 37.🔋 8 identical 2 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
38. 38.True or false: the ammeter measures voltage. (a) False (b) True
39. 39.🔐 Is it a good or a risky habit to cover unused cameras? (a) good habit (b) risky habit
40. 40.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?

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