Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 854 · 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 drawing is the symbol for a bulb? (a) a circle with M inside (b) a plain rectangle (c) a circle with an X in it (d) a line lifted at a gap
2. 2.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
3. 3.🧩 Which component makes a beeping sound? (a) thermistor (b) transistor (c) diode (d) buzzer
4. 4.🔋 How many volts does one ordinary torch cell give? (a) 0.5 V (b) 230 V (c) 1.5 V (d) 15 V
5. 5.Which of these mainly makes movement? (a) a tube light (b) an LED lamp (c) a night lamp (d) a ceiling fan
6. 6.🔁 count = 4
   repeat 8 times { count = count + 8 }
   What is count at the end?
7. 7.📶 Digital or analog: a button: pressed or not? (a) analog (b) digital
8. 8.🔗 Series or parallel circuit: “one bulb out, all go out”? (a) series (b) parallel
9. 9.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 5 V supply. What current flows (in mA)?
10. 10.Which of these means the circuit is open? (a) a wire has come loose (b) the loop is complete (c) the switch is ON (d) all wires are joined
11. 11.Which job needs a temperature sensor? (a) water a dry plant (b) stop a robot near walls (c) keep an incubator warm (d) switch on with a clap
12. 12.🔁 count = 4
    while (count < 12) { count = count + 2 }
    How many times does the loop run?
13. 13.🔍 Which is the odd one out? (a) an electric iron (b) an LED lamp (c) an electric kettle (d) a rice cooker
14. 14.🔍 A distance sensor sends a sound pulse and hears the echo 12 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
15. 15.🔺 A current of 25 mA flows when 3.75 V is joined across a resistor. What is its resistance (in ohms)?
16. 16.🤖 Microcontroller or laptop: which one needs much more power? (a) microcontroller (b) laptop
17. 17.🔍 Which is the odd one out? (a) a wind-up clock (b) a plain table fan (c) an app-controlled bulb (d) a paper calendar
18. 18.🔍 Which is the odd one out? (a) aluminium foil (b) a dry cork (c) a woollen thread (d) a paper strip
19. 19.True or false: to use a cable with cuts is not safe. (a) True (b) False
20. 20.Which of these wastes electricity? (a) iron one shirt at a time (b) close the fridge quickly (c) switch off empty rooms (d) unplug idle chargers
21. 21.🔁 What does a variable do in a program? (a) joins two wires (b) measures light (c) blinks an LED (d) stores a value
22. 22.🤖 if (temperature > 37) { show “Hot” } else if (temperature > 25) { show “Warm” } else { show “Cool” }
    The temperature is 34 °C. What is shown? (a) Hot (b) Warm (c) Cool
23. 23.💡 5 identical bulbs are joined in series with a 20 V battery (ideal wires). How many volts does each bulb get? =
24. 24.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
25. 25.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 HIGH
    set pin 8 LOW
    set pin 7 LOW
    set pin 8 LOW
    set pin 8 LOW
    Is the LED ON or OFF at the end? (a) OFF (b) ON
26. 26.True or false: a circle with M inside is the symbol for a voltmeter. (a) True (b) False
27. 27.🤖 if (light < 400 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 60 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON
28. 28.🔋 A 9 V battery and three 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
29. 29.📏 Which unit measures power? (a) watt (W) (b) ampere (A) (c) ohm (Ω) (d) volt (V)
30. 30.🤖 if (light < 200 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 490 and motion is detected (true). What happens? (a) porch lamp OFF (b) porch lamp ON
31. 31.🤖 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
32. 32.⏱️ loop forever { LED ON; wait 750 ms; LED OFF; wait 250 ms }
    How many times does the LED blink in 10 seconds?
33. 33.🧾 A family uses 30 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
34. 34.🔋 What should you do with used-up cells? (a) throw them in a fire (b) give them for recycling (c) cut them open (d) bury them in soil
35. 35.🔌 Is a turning knob an input or an output for a microcontroller? (a) output (b) input
36. 36.🔺 A current of 0.1 A flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
37. 37.🧩 Which component limits the current? (a) diode (b) capacitor (c) LED (d) resistor
38. 38.🔺 A current of 1.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
39. 39.🔺 A current of 0.1 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
40. 40.True or false: a small empty box is the symbol for a bulb. (a) False (b) True

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