Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 761 · 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 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
2. 2.🔍 Which is the odd one out? (a) use old filament bulbs (b) unplug idle chargers (c) switch off empty rooms (d) set the AC to 24 °C
3. 3.✏️ Why do engineers draw circuits with symbols? (a) symbols are heavier (b) quick and clear for all (c) to make it colourful (d) to hide the circuit
4. 4.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a capacitor (c) a resistor (d) a diode
5. 5.💡 2 identical bulbs are joined in parallel across a 6 V battery (ideal wires). How many volts does each bulb get? =
6. 6.True or false: to change default passwords is a risky habit. (a) True (b) False
7. 7.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
8. 8.🔋 What should you do with used-up cells? (a) give them for recycling (b) bury them in soil (c) cut them open (d) throw them in a fire
9. 9.🤖 if (moisture < 50) { pump ON } else { pump OFF }
   The soil moisture sensor reads 65 %. What happens? (a) pump OFF (b) pump ON
10. 10.⚡ What does a school bell mainly change electricity into? (a) sound (b) light (c) heat (d) movement
11. 11.True or false: a small empty box is the symbol for an ammeter. (a) True (b) False
12. 12.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) smaller (c) zero (d) bigger
13. 13.🔌 Is a copper wire a conductor or an insulator? (a) a conductor (b) an insulator
14. 14.True or false: an LED glows using little power. (a) False (b) True
15. 15.True or false: to switch on with a clap, use a sound sensor. (a) False (b) True
16. 16.Which job needs a pump? (a) open a gate to 90° (b) turn to an exact angle (c) beep an alarm (d) move water to plants
17. 17.✏️ In a circuit diagram, which part is drawn as a circle with a cross? (a) resistor (b) LED (c) bulb (d) ammeter
18. 18.🔍 An object is 51 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
19. 19.🔁 total = 0
    for i = 1 to 11 { total = total + i }
    What is total at the end?
20. 20.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
21. 21.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. Does the bulb glow? (a) No (b) Yes
22. 22.True or false: to share only needed data is a risky habit. (a) False (b) True
23. 23.🤖 if (temperature > 38) { show “Hot” } else if (temperature > 24) { show “Warm” } else { show “Cool” }
    The temperature is 34 °C. What is shown? (a) Warm (b) Cool (c) Hot
24. 24.🤖 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
25. 25.Which of these is an output? (a) a push button (b) a light sensor (c) a speaker (d) a temperature sensor
26. 26.🤖 if (light < 400 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 420 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON
27. 27.True or false: “a light level reading” is the output. (a) False (b) True
28. 28.🌐 A soil sensor sends a reading to an app every 20 minutes. How many readings arrive in 1 hour?
29. 29.⚠️ Is it safe to build with an adult near? (a) safe (b) not safe
30. 30.📶 A pin that reads a push button is set as … (a) an output (b) an input (c) a battery (d) a resistor
31. 31.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. A gap in one wire is bridged by a woollen thread. Does the bulb glow? (a) No (b) Yes
32. 32.🌐 What does IoT stand for? (a) Internet of Things (b) Internet of Talk (c) Input of Tools (d) Inside of Toys
33. 33.⏱️ How many milliseconds are in 1 second? (a) 100 (b) 60 (c) 1000 (d) 10
34. 34.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V × R (c) I = V + R (d) I = V ÷ R
35. 35.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3 V supply. What current flows (in mA)?
36. 36.🔘 Which kind of switch works only while pressed? (a) a slide switch (b) a reed switch (c) a push button (d) a toggle switch
37. 37.🔺 A current of 3 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
38. 38.True or false: to run fans in empty rooms wastes electricity. (a) False (b) True
39. 39.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V × I (d) P = V + I
40. 40.🔺 A 5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?

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