Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 825 · 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 8. All pins start LOW. The program runs once:
   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
2. 2.True or false: a push button slides side to side. (a) False (b) True
3. 3.🧭 Which part of a microcontroller board shows the board is on? (a) the main chip (b) the USB port (c) the pins (d) the power LED
4. 4.🔋 How many 2 V cells must be joined in series to give 6 V?
5. 5.🤖 if (distance < 20) { buzzer beeps } else { buzzer is silent }
   The distance sensor reads 25 cm. What happens? (a) buzzer beeps (b) buzzer is silent
6. 6.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) zero (c) bigger (d) stay the same
7. 7.True or false: on a cell, “usually the red wire” means the − (negative) end. (a) True (b) False
8. 8.🔌 Is a brass key a conductor or an insulator? (a) an insulator (b) a conductor
9. 9.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it makes a sound (c) it changes colour (d) it does not light
10. 10.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) neither part (b) both parts (c) the if part (d) the else part
11. 11.Which of these saves electricity? (a) unplug idle chargers (b) leave fridge door open (c) use old filament bulbs (d) run fans in empty rooms
12. 12.🔺 A 3 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
13. 13.🤖 if (temperature > 34) { show “Hot” } else if (temperature > 20) { show “Warm” } else { show “Cool” }
    The temperature is 27 °C. What is shown? (a) Hot (b) Cool (c) Warm
14. 14.🌈 In the resistor colour code, which number does brown stand for?
15. 15.True or false: a buzzer lets current go one way. (a) True (b) False
16. 16.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
17. 17.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
18. 18.💡 In a series circuit, how many paths does the current have? (a) one (b) one for each bulb (c) none (d) two
19. 19.🔺 A 4 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
20. 20.🔘 A cell and a bulb are joined to 4 side-by-side paths with one switch on each path — A, B, C and D (parallel). A is ON, B is ON, C is ON and D is ON. Does the bulb glow? (a) Yes (b) No
21. 21.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 8 HIGH
    set pin 7 HIGH
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) OFF (b) ON
22. 22.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
23. 23.True or false: a thermistor blows if current is high. (a) True (b) False
24. 24.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
25. 25.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 890 Ω resistor? (a) grey-white-brown (b) grey-white-black (c) white-grey-brown (d) grey-white-red
26. 26.🔁 repeat 5 times { repeat 2 times { beep } }
    How many beeps are there?
27. 27.True or false: a microcontroller runs one small program. (a) False (b) True
28. 28.True or false: a diode makes a beeping sound. (a) False (b) True
29. 29.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
30. 30.⚙️ Which actuator would you use to spin a robot’s wheels? (a) a motor (b) a buzzer (c) an LED (d) a display
31. 31.🔘 Which kind of switch flips up or down? (a) a slide switch (b) a tilt switch (c) a toggle switch (d) a push button
32. 32.⚠️ Is it safe to keep drinks far away? (a) safe (b) not safe
33. 33.⚠️ About how many volts do home sockets in India supply? (a) 12 V (b) 230 V (c) 9 V (d) 1.5 V
34. 34.💡 An LED is joined to a 3 V battery through a 1000 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) may burn out (c) lights up
35. 35.Which of these is an input? (a) a water pump (b) a motor (c) a buzzer (d) a temperature sensor
36. 36.🔘 Two switches are in parallel (side by side). When does the bulb glow? (a) never (b) when either is ON (c) only when both are OFF (d) only when both are ON
37. 37.True or false: a laptop runs one small program. (a) True (b) False
38. 38.🔺 A current of 25 mA flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
39. 39.🔁 repeat 5 times { repeat 3 times { beep } }
    How many beeps are there?
40. 40.Which of these mainly gives out heat? (a) an LED lamp (b) an electric toy car (c) a rice cooker (d) a table fan

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