Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 840 · 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.True or false: a woollen thread is an insulator. (a) False (b) True
2. 2.True or false: to reuse one password is a good habit. (a) True (b) False
3. 3.What does a push button do? (a) stays where you flip it (b) closes when tipped over (c) works only while pressed (d) slides side to side
4. 4.🔘 Two switches are in series. When does the bulb glow? (a) when either is ON (b) never (c) when both are OFF (d) when both are ON
5. 5.🔺 A current of 25 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
6. 6.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) stays the same (c) gets smaller (d) becomes zero
7. 7.What does a transistor do? (a) limits the current (b) is a resistance knob (c) boosts a small signal (d) turns a fan or wheels
8. 8.Which of these mainly gives out light? (a) a water heater (b) a room heater (c) an LED lamp (d) a ceiling fan
9. 9.Which drawing is the symbol for an ammeter? (a) two equal parallel lines (b) a circle with A inside (c) many long-short pairs (d) a dot where wires meet
10. 10.⏱️ repeat 8 times { buzzer ON; wait 500 ms; buzzer OFF; wait 100 ms }
    How many milliseconds does this take in all?
11. 11.🧾 A family uses 50 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
12. 12.Which of these saves electricity? (a) leave fridge door open (b) run fans in empty rooms (c) close the fridge quickly (d) leave the TV on standby
13. 13.⚙️ Which actuator would you use to show the temperature? (a) a display (b) a buzzer (c) an LED (d) a pump
14. 14.🔺 A 37.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
15. 15.Which of these is not an IoT device? (a) a Wi-Fi doorbell camera (b) a fitness band with app (c) a battery torch (d) a Wi-Fi weather station
16. 16.🤖 if (light < 300 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 70 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON
17. 17.💡 A battery lights 4 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) the same (b) brighter (c) dimmer
18. 18.🔁 x = 3
    repeat 1 time { x = x × 2 }
    What is x at the end?
19. 19.🔍 Which is the odd one out? (a) a steel spoon (b) a graphite rod (c) a glass marble (d) a safety pin
20. 20.🔺 A current of 2.5 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
21. 21.🔁 count = 2
    while (count < 12) { count = count + 5 }
    How many times does the loop run?
22. 22.🔺 A current of 0.2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
23. 23.Which job needs an LED? (a) show a status light (b) show the temperature (c) beep an alarm (d) move water to plants
24. 24.🔘 What does a switch do in a circuit? (a) changes the voltage (b) makes electricity (c) stores current (d) opens or closes the loop
25. 25.True or false: “used in house wiring” is true of a series circuit. (a) False (b) True
26. 26.Which of these usually has a microcontroller inside? (a) a washing machine (b) a bicycle bell (c) a plain wall switch (d) a hand pump
27. 27.🤖 if (temperature > 37) { show “Hot” } else if (temperature > 20) { show “Warm” } else { show “Cool” }
    The temperature is 44 °C. What is shown? (a) Cool (b) Warm (c) Hot
28. 28.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 ampere (c) 1 kilowatt-hour (kWh) (d) 1 volt
29. 29.🤖 Does a candle usually have a microcontroller inside? (a) No (b) Yes
30. 30.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 7 HIGH
    set pin 8 HIGH
    set pin 7 LOW
    set pin 8 LOW
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF
31. 31.🔁 count = 9
    repeat 9 times { count = count + 2 }
    What is count at the end?
32. 32.🔁 x = 1
    repeat 2 times { x = x × 2 }
    What is x at the end?
33. 33.True or false: to install software updates is a risky habit. (a) True (b) False
34. 34.Which of these uses electricity? (a) a bicycle dynamo (b) a washing machine (c) a cell (d) a power station
35. 35.✏️ Why do engineers draw circuits with symbols? (a) symbols are heavier (b) to make it colourful (c) quick and clear for all (d) to hide the circuit
36. 36.⚡ A 36 W device works on 12 V. What current does it take (in amperes)? =
37. 37.🔺 A current of 3 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
38. 38.💡 In a series circuit, how many paths does the current have? (a) two (b) none (c) one for each bulb (d) one
39. 39.🧩 A capacitor in a circuit can … (a) store charge briefly (b) make light (c) spin a wheel (d) measure heat
40. 40.🔘 Two switches are in parallel (side by side). When does the bulb glow? (a) only when both are OFF (b) when either is ON (c) only when both are ON (d) never

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