Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 489 · 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.⏱️ loop forever { LED ON; wait 450 ms; LED OFF; wait 150 ms }
   How many milliseconds does one blink (ON + OFF) take?
2. 2.🤖 if (sound > 60) { red LED ON } else { green LED ON }
   The sound sensor reads 56. What happens? (a) red LED ON (b) green LED ON
3. 3.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
4. 4.Which of these is safe? (a) open a phone charger (b) climb an electric pole (c) use a cable with cuts (d) stop if a part gets hot
5. 5.True or false: a wind-up toy usually has a microcontroller inside. (a) True (b) False
6. 6.True or false: a tilt switch closes near a magnet. (a) False (b) True
7. 7.True or false: “one bulb out, all go out” is true of a series circuit. (a) True (b) False
8. 8.True or false: a circle with a cross is the symbol for a bulb. (a) True (b) False
9. 9.Which job is done by the reset button? (a) shows the board is on (b) runs the program (c) keeps the voltage steady (d) restarts the program
10. 10.🔍 Which sensor would you use to open blinds at sunrise? (a) a distance sensor (b) a light sensor (c) a rain sensor (d) a motion sensor
11. 11.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 400 ms }
    How many times does the LED blink in 1 second?
12. 12.True or false: to use daylight to read saves electricity. (a) False (b) True
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 7 HIGH
    set pin 7 HIGH
    set pin 8 HIGH
    Is the LED ON or OFF at the end? (a) OFF (b) ON
14. 14.💡 5 identical bulbs are joined in series with a 7.5 V battery (ideal wires). How many volts does each bulb get? =
15. 15.⚡ A cell changes stored chemical energy into which kind of energy? (a) wind energy (b) nuclear energy (c) electrical energy (d) sound energy
16. 16.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a wooden stick across the gap. Does the bulb glow? (a) No (b) Yes
17. 17.True or false: on a cell, “usually the black wire” means the − (negative) end. (a) True (b) False
18. 18.🔗 Series or parallel circuit: “bulbs share the voltage”? (a) series (b) parallel
19. 19.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = V + R (c) I = R ÷ V (d) I = V ÷ R
20. 20.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
21. 21.⏱️ repeat 5 times { buzzer ON; wait 300 ms; buzzer OFF; wait 700 ms }
    How many milliseconds does this take in all?
22. 22.✏️ In a cell symbol, which line is the + terminal? (a) the shorter line (b) neither line (c) both lines (d) the longer line
23. 23.🔍 Which sensor would you use to start a fan when hot? (a) a rain sensor (b) a sound sensor (c) a motion sensor (d) a temperature sensor
24. 24.⚙️ What is an actuator? (a) a battery (b) a sensor (c) a program (d) an output that acts
25. 25.⏱️ repeat 8 times { buzzer ON; wait 400 ms; buzzer OFF; wait 1000 ms }
    How many milliseconds does this take in all?
26. 26.What does the sensor do? (a) carries the data (b) acts on a command (c) measures the real world (d) shows data to you
27. 27.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the if part (b) both parts (c) the else part (d) neither part
28. 28.💡 3 identical bulbs are in parallel and each bulb has its own switch on its path. 1 of the switches is OFF and the rest are ON. How many bulbs glow?
29. 29.🧾 A family uses 190 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
30. 30.💡 A battery lights 3 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) brighter (b) the same (c) dimmer
31. 31.🔘 Two switches are in parallel (side by side). When does the bulb glow? (a) only when both are ON (b) when either is ON (c) only when both are OFF (d) never
32. 32.Which of these is true of a parallel circuit? (a) one bulb out, all go out (b) a single current path (c) bulbs share the voltage (d) many paths for current
33. 33.Which of these is a conductor? (a) a woollen thread (b) a cotton thread (c) a graphite rod (d) a rubber band
34. 34.🔍 Which is the odd one out? (a) use a cable with cuts (b) fly a kite near wires (c) climb an electric pole (d) dry your hands first
35. 35.🤖 if (light < 300 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 70 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
36. 36.🔁 x = 3
    repeat 4 times { x = x × 2 }
    What is x at the end?
37. 37.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 100 ms }
    How many times does the LED blink in 9 seconds?
38. 38.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
39. 39.🔐 A smart speaker is always listening for its wake word. What is a sensible habit? (a) put it in the bathroom (b) let strangers use it (c) mute it when not in use (d) tell it your passwords
40. 40.⚙️ Which actuator would you use to turn to an exact angle? (a) a motor (b) a servo motor (c) a display (d) a pump

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