Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 654 · 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.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
   set pin 7 HIGH
   set pin 8 HIGH
   Is the LED ON or OFF at the end? (a) OFF (b) ON
2. 2.True or false: “one out, the rest glow” is true of a parallel circuit. (a) True (b) False
3. 3.Which of these is an IoT device? (a) a plain wall switch (b) a pencil sharpener (c) an app-controlled bulb (d) a battery torch
4. 4.⚡ A fan changes electrical energy mainly into which kind of energy? (a) sound energy (b) light energy (c) movement energy (d) chemical energy
5. 5.Which of these mainly makes sound? (a) a doorbell (b) a table fan (c) an electric iron (d) a room heater
6. 6.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
7. 7.🤖 if (temperature > 31) { show “Hot” } else if (temperature > 20) { show “Warm” } else { show “Cool” }
   The temperature is 11 °C. What is shown? (a) Hot (b) Cool (c) Warm
8. 8.Which of these means the circuit is open? (a) the loop is complete (b) a wire has come loose (c) the switch is ON (d) all wires are joined
9. 9.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
10. 10.⏱️ loop forever { LED ON; wait 700 ms; LED OFF; wait 400 ms }
    How many milliseconds does one blink (ON + OFF) take?
11. 11.⏱️ A program says “wait 500 ms”. How many seconds is that? =
12. 12.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) becomes zero (c) gets smaller (d) stays the same
13. 13.🔺 A current of 50 mA flows when 23.5 V is joined across a resistor. What is its resistance (in ohms)?
14. 14.🔌 Is a dry cork a conductor or an insulator? (a) a conductor (b) an insulator
15. 15.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = I ÷ V (c) P = V × I (d) P = V + I
16. 16.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) by Wi-Fi (b) in series (c) in parallel (d) not joined
17. 17.True or false: a circle with A inside is the symbol for an ammeter. (a) True (b) False
18. 18.🔍 An object is 68 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
19. 19.⏱️ How many milliseconds are in 1 second? (a) 60 (b) 100 (c) 10 (d) 1000
20. 20.🌈 A resistor has the colour bands blue, blue, yellow. What is its value in kilo-ohms (kΩ)? =
21. 21.✏️ In a circuit diagram, which part is drawn as a circle with A inside? (a) wire (b) ammeter (c) junction (d) resistor
22. 22.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 8 HIGH
    set pin 7 LOW
    set pin 7 LOW
    set pin 7 LOW
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) OFF (b) ON
23. 23.⚠️ About how many volts do home sockets in India supply? (a) 230 V (b) 1.5 V (c) 9 V (d) 12 V
24. 24.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the filament (d) the glass
25. 25.🗺️ In an input → process → output plan, is “the pump turns on” the input, the process or the output? (a) input (b) output (c) process
26. 26.🔍 Which sensor would you use to stop a robot near walls? (a) a sound sensor (b) a rain sensor (c) a light sensor (d) a distance sensor
27. 27.True or false: a rubber eraser is an insulator. (a) False (b) True
28. 28.⏱️ loop forever { LED ON; wait 250 ms; LED OFF; wait 250 ms }
    How many times does the LED blink in 6 seconds?
29. 29.True or false: to throw cells in a fire is safe. (a) True (b) False
30. 30.⏱️ repeat 8 times { buzzer ON; wait 100 ms; buzzer OFF; wait 600 ms }
    How many milliseconds does this take in all?
31. 31.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
32. 32.What does a fuse do? (a) blows if current is high (b) boosts a small signal (c) makes things spin (d) stores a little charge
33. 33.🔁 What must there be for a current to flow? (a) a plastic gap (b) one loose end (c) a broken path (d) a complete loop
34. 34.Which drawing is the symbol for a switch? (a) a small empty box (b) a straight line (c) two or more cell symbols (d) a line lifted at a gap
35. 35.🧭 Which part of a microcontroller board connect sensors and LEDs? (a) the voltage regulator (b) the USB port (c) the pins (d) the reset button
36. 36.🔺 A 37.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
37. 37.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = R ÷ I (c) V = I ÷ R (d) V = I × R
38. 38.🤖 What is a microcontroller? (a) a type of battery (b) a big desktop computer (c) a computer on one chip (d) a kind of bulb
39. 39.Which drawing is the symbol for a battery? (a) a circle with a cross (b) a circle with A inside (c) many long-short pairs (d) a dot where wires meet
40. 40.True or false: a circle with V inside is the symbol for a diode. (a) True (b) False

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