Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 369 · 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.🔁 What must there be for a current to flow? (a) a plastic gap (b) a broken path (c) a complete loop (d) one loose end
2. 2.🔍 Which is the odd one out? (a) cover unused cameras (b) accept every permission (c) share only needed data (d) change default passwords
3. 3.🧾 A family uses 90 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
4. 4.⏱️ How many milliseconds are in 1 second? (a) 1000 (b) 10 (c) 60 (d) 100
5. 5.🤖 if (distance < 15) { buzzer beeps } else { buzzer is silent }
   The distance sensor reads 23 cm. What happens? (a) buzzer is silent (b) buzzer beeps
6. 6.🔢 To run one loop of a plant-watering program, which comes first: “compare with the limit” or “wait a few seconds”? (a) wait a few seconds (b) compare with the limit
7. 7.Which of these is an IoT device? (a) a plain table fan (b) a pencil sharpener (c) a Wi-Fi doorbell camera (d) a plain wall switch
8. 8.🤖 if (moisture < 40) { pump ON } else { pump OFF }
   The soil moisture sensor reads 23 %. What happens? (a) pump OFF (b) pump ON
9. 9.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
10. 10.🔌 Is a woollen thread a conductor or an insulator? (a) an insulator (b) a conductor
11. 11.True or false: to iron one shirt at a time wastes electricity. (a) True (b) False
12. 12.⏱️ What does “wait 500 ms” do? (a) turns the LED off (b) waits 500 seconds (c) pauses for half a second (d) blinks 500 times
13. 13.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 8 LOW
    set pin 7 HIGH
    set pin 7 HIGH
    set pin 7 HIGH
    Is the LED ON or OFF at the end? (a) ON (b) OFF
14. 14.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the if part (b) neither part (c) the else part (d) both parts
15. 15.✏️ In a circuit diagram, which part is drawn as two or more cell symbols? (a) switch (b) bulb (c) capacitor (d) battery
16. 16.🧩 Which part changes electrical energy into movement? (a) a motor (b) an LED (c) a fuse (d) a resistor
17. 17.🔺 A current of 2.5 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
18. 18.🤖 “if (A AND B)” is true when … (a) only A is true (b) both A and B are true (c) only B is true (d) both are false
19. 19.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
20. 20.🔌 Is a water pump an input or an output for a microcontroller? (a) output (b) input
21. 21.True or false: many long-short pairs is the symbol for a battery. (a) True (b) False
22. 22.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 400 ms }
    How many milliseconds does one blink (ON + OFF) take?
23. 23.💡 4 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 4 is taken out of its holder. How many bulbs glow?
24. 24.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
25. 25.🔺 A current of 20 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
26. 26.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a safety pin across the gap. Does the bulb glow? (a) Yes (b) No
27. 27.Which drawing is the symbol for a resistor? (a) a small empty box (b) one tall, one short bar (c) two equal parallel lines (d) a circle with V inside
28. 28.🔍 Which is the odd one out? (a) use mains for a project (b) poke things in a socket (c) throw cells in a fire (d) keep drinks far away
29. 29.Which of these gives us electricity? (a) a solar panel (b) a computer (c) a washing machine (d) a mobile phone
30. 30.⏱️ repeat 2 times { buzzer ON; wait 900 ms; buzzer OFF; wait 900 ms }
    How many milliseconds does this take in all?
31. 31.Which of these gives us electricity? (a) a television (b) a mobile phone (c) a power station (d) a washing machine
32. 32.Which job needs a servo motor? (a) show a status light (b) beep an alarm (c) open a gate to 90° (d) spin a robot’s wheels
33. 33.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 7 HIGH
    set pin 7 LOW
    set pin 8 LOW
    set pin 7 HIGH
    Is the LED ON or OFF at the end? (a) OFF (b) ON
34. 34.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
35. 35.True or false: to fly a kite near wires is safe. (a) False (b) True
36. 36.What does the microcontroller do? (a) stores data online (b) shows data to you (c) carries the data (d) reads values, decides
37. 37.True or false: “a tilt switch: on or off” is a digital signal. (a) True (b) False
38. 38.🔐 Who should decide which smart devices go in a child’s room? (a) a parent or guardian (b) the app’s adverts (c) nobody at all (d) an online stranger
39. 39.🔍 Which is the odd one out? (a) a toaster (b) a buzzer (c) a rice cooker (d) a water heater
40. 40.🧮 Resistors of 68 Ω, 470 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?

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