Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 789 · 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 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
2. 2.🔺 In the V-I-R triangle, how do we find R? (a) R = V ÷ I (b) R = I ÷ V (c) R = V × I (d) R = V + I
3. 3.True or false: a slide switch slides side to side. (a) True (b) False
4. 4.Which of these mainly gives out light? (a) an electric iron (b) an exhaust fan (c) a mixer grinder (d) a tube light
5. 5.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) − (negative) (b) + (positive)
6. 6.Which of these mainly makes movement? (a) a torch (b) a siren (c) a table fan (d) an electric iron
7. 7.Which of these is a good habit? (a) keep factory passwords (b) post your live location (c) install software updates (d) share the Wi-Fi key
8. 8.Which job needs an LED? (a) spin a robot’s wheels (b) show a status light (c) beep an alarm (d) move water to plants
9. 9.💡 A battery lights 2 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) brighter (b) the same (c) dimmer
10. 10.🌈 Which band is read first on a resistor? (a) the gold band (b) the widest gap (c) any band (d) the one nearest an end
11. 11.🔺 A 0.75 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
12. 12.🤖 if (temperature > 30) { fan ON } else { fan OFF }
    The temperature sensor reads 33 °C. What happens? (a) fan OFF (b) fan ON
13. 13.🔢 To plan an electronics project, what comes right after “pick a problem to solve”? (a) list inputs and outputs (b) build it with an adult (c) test it and fix it (d) draw the circuit diagram
14. 14.💡 A battery lights 5 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) the same (b) dimmer (c) brighter
15. 15.What does an LDR do? (a) glows using little power (b) senses how bright it is (c) blows if current is high (d) beeps for an alarm
16. 16.True or false: to switch on lamps at dusk, use a distance sensor. (a) False (b) True
17. 17.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a woollen thread across the gap. Does the bulb glow? (a) Yes (b) No
18. 18.🧩 Which component makes a beeping sound? (a) potentiometer (b) buzzer (c) motor (d) thermistor
19. 19.🌐 How does a home IoT device usually send its data to the app? (a) through a candle (b) over Wi-Fi (c) by post (d) by shouting
20. 20.🔍 Which sensor would you use to switch on lamps at dusk? (a) a sound sensor (b) a light sensor (c) a rain sensor (d) a motion sensor
21. 21.True or false: a siren mainly gives out light. (a) True (b) False
22. 22.⚠️ About how many volts do home sockets in India supply? (a) 1.5 V (b) 12 V (c) 9 V (d) 230 V
23. 23.💡 3 identical bulbs are joined in parallel across a 3 V battery (ideal wires). How many volts does each bulb get? =
24. 24.🌐 A weather station sends one reading every 5 seconds. How many readings does it send in 10 minutes?
25. 25.🔘 Which kind of switch slides side to side? (a) a push button (b) a slide switch (c) a toggle switch (d) a reed switch
26. 26.Which of these is measured in watts (W)? (a) energy used each second (b) the flow of charge (c) the push of a cell (d) how much a part resists
27. 27.True or false: to open blinds at sunrise, use a light sensor. (a) True (b) False
28. 28.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V × I (d) P = V ÷ I
29. 29.📏 Which unit measures how much a part resists? (a) ampere (A) (b) ohm (Ω) (c) watt (W) (d) volt (V)
30. 30.True or false: a resistor has coloured bands. (a) False (b) True
31. 31.Which of these saves electricity? (a) use old filament bulbs (b) use daylight to read (c) leave fridge door open (d) run fans in empty rooms
32. 32.What does a toggle switch do? (a) works only while pressed (b) flips up or down (c) slides side to side (d) closes near a magnet
33. 33.Which of these is a risky habit? (a) change default passwords (b) ignore update messages (c) set up with a parent (d) share only needed data
34. 34.Which of these usually has a microcontroller inside? (a) a hand pump (b) a plain wall switch (c) a wind-up toy (d) a microwave oven
35. 35.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a cotton thread. Does the bulb glow? (a) No (b) Yes
36. 36.💡 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?
37. 37.📶 Digital or analog: a tilt switch: on or off? (a) analog (b) digital
38. 38.🔺 A current of 50 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
39. 39.🔐 Is it a good or a risky habit to cover unused cameras? (a) good habit (b) risky habit
40. 40.⏱️ A program says “wait 9250 ms”. How many seconds is that? =

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