Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 745 · 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 of these is not safe? (a) stay away from pylons (b) keep drinks far away (c) build with an adult near (d) climb an electric pole
2. 2.🌈 A resistor has the colour bands yellow, red, black. What is its value (in ohms)?
3. 3.🔁 x = 2
   repeat 1 time { x = x × 2 }
   What is x at the end?
4. 4.🔐 Who should decide which smart devices go in a child’s room? (a) the app’s adverts (b) an online stranger (c) nobody at all (d) a parent or guardian
5. 5.True or false: to keep factory passwords is a good habit. (a) False (b) True
6. 6.🔋 How many volts does one ordinary torch cell give? (a) 0.5 V (b) 1.5 V (c) 230 V (d) 15 V
7. 7.🔢 To get a sensor reading onto a phone, which is the FIRST step? (a) it is sent by Wi-Fi (b) the board reads it (c) the app shows it (d) the sensor measures
8. 8.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 50 ms }
   How many times does the LED blink in 6 seconds?
9. 9.What does the sensor do? (a) reads values, decides (b) stores data online (c) measures the real world (d) acts on a command
10. 10.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 8 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF
11. 11.🔍 Which is the odd one out? (a) a water heater (b) an electric iron (c) a rice cooker (d) a school bell
12. 12.🔺 A current of 40 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
13. 13.True or false: “a light level reading” is the input. (a) True (b) False
14. 14.🔋 Does a computer give electricity or use electricity? (a) uses electricity (b) gives electricity
15. 15.Which of these is a risky habit? (a) share only needed data (b) read app permissions (c) share the Wi-Fi key (d) turn off unused gadgets
16. 16.🧾 A family uses 110 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
17. 17.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) + (positive) (b) − (negative)
18. 18.Which of these is safe? (a) dry your hands first (b) touch a fallen wire (c) poke things in a socket (d) touch a switch when wet
19. 19.True or false: to fly kites in open fields is not safe. (a) True (b) False
20. 20.Which of these mainly makes movement? (a) a siren (b) an electric iron (c) a ceiling fan (d) a toaster
21. 21.True or false: “a button press” is the process. (a) True (b) False
22. 22.🔋 6 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
23. 23.🔋 Does a refrigerator give electricity or use electricity? (a) gives electricity (b) uses electricity
24. 24.True or false: “a button: pressed or not” is an analog signal. (a) False (b) True
25. 25.⏱️ How many milliseconds is a wait of 2 seconds?
26. 26.🔦 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
27. 27.⏱️ loop forever { LED ON; wait 50 ms; LED OFF; wait 350 ms }
    How many times does the LED blink in 18 seconds?
28. 28.💡 Why is house wiring done in parallel? (a) so all go off together (b) to save copper only (c) to make bulbs dim (d) each gets full voltage
29. 29.Which drawing is the symbol for a wire? (a) a plain rectangle (b) two equal parallel lines (c) a circle with a cross (d) a straight line
30. 30.💡 5 identical bulbs are in parallel and each bulb has its own switch on its path. 3 of the switches are OFF and the rest are ON. How many bulbs glow?
31. 31.🔌 Is a speaker an input or an output for a microcontroller? (a) output (b) input
32. 32.🔍 Which sensor would you use to water a dry plant? (a) a gas sensor (b) a temperature sensor (c) a soil moisture sensor (d) a light sensor
33. 33.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a glass marble across the gap. Does the bulb glow? (a) No (b) Yes
34. 34.⏱️ repeat 8 times { buzzer ON; wait 300 ms; buzzer OFF; wait 700 ms }
    How many milliseconds does this take in all?
35. 35.💡 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
36. 36.🔘 A bulb and a cell are joined through 2 switches one after another in a single loop (series). What is the smallest number of switches that must be ON to light the bulb?
37. 37.True or false: the voltmeter measures current. (a) True (b) False
38. 38.🤖 if (light < 200 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 310 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON
39. 39.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
40. 40.🔐 Is it a good or a risky habit to cover unused cameras? (a) risky habit (b) good habit

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