Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 730 · 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.⚠️ Is it safe to dry your hands first? (a) not safe (b) safe
2. 2.🔐 Is it a good or a risky habit to set a strong password? (a) risky habit (b) good habit
3. 3.🔘 Switch A is on the main wire next to the cell and the bulb; then the wire splits into two side-by-side paths, one with switch B and one with switch C. A is ON, B is ON and C is OFF. Does the bulb glow? (a) No (b) Yes
4. 4.🔺 A 30 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
5. 5.True or false: on a cell, “the flat end” means the − (negative) end. (a) False (b) True
6. 6.🔦 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
7. 7.⏱️ repeat 2 times { buzzer ON; wait 300 ms; buzzer OFF; wait 200 ms }
   How many milliseconds does this take in all?
8. 8.✏️ In a circuit diagram, wires are usually drawn as … (a) straight lines (b) little stars (c) dotted circles (d) wavy lines
9. 9.🔍 Which is the odd one out? (a) a smart energy meter (b) a Wi-Fi doorbell camera (c) a Wi-Fi weather station (d) a pencil sharpener
10. 10.Which drawing is the symbol for a wire? (a) a circle with an X in it (b) a straight line (c) two or more cell symbols (d) many long-short pairs
11. 11.🔋 On a cell, does “the flat end” mean the + end or the − end? (a) + (positive) (b) − (negative)
12. 12.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 7300 Ω resistor? (a) violet-orange-brown (b) violet-orange-orange (c) orange-violet-red (d) violet-orange-red
13. 13.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 8 HIGH
    set pin 7 LOW
    set pin 7 HIGH
    set pin 8 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF
14. 14.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) smaller (c) zero (d) bigger
15. 15.Which of these wastes electricity? (a) run fans in empty rooms (b) switch off empty rooms (c) use LED lamps (d) unplug idle chargers
16. 16.True or false: to use mains for a project is not safe. (a) False (b) True
17. 17.🤖 if (distance < 15) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 24 cm. What happens? (a) buzzer beeps (b) buzzer is silent
18. 18.True or false: a potentiometer lets current go one way. (a) False (b) True
19. 19.True or false: a diode stores a little charge. (a) False (b) True
20. 20.🔺 A current of 25 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
21. 21.⚡ Power tells us … (a) the length of a wire (b) the colour of light (c) the size of a cell (d) energy used each second
22. 22.True or false: “a motion sensor signal” is the process. (a) False (b) True
23. 23.🔁 repeat 4 times { repeat 3 times { beep } }
    How many beeps are there?
24. 24.🔋 What should you do with used-up cells? (a) throw them in a fire (b) cut them open (c) give them for recycling (d) bury them in soil
25. 25.⏱️ A program says “wait 8750 ms”. How many seconds is that? =
26. 26.Which of these has no microcontroller inside? (a) a toy robot (b) a smart watch (c) a bicycle bell (d) a microwave oven
27. 27.🔍 Which is the odd one out? (a) leave fridge door open (b) close the fridge quickly (c) run fans in empty rooms (d) iron one shirt at a time
28. 28.🔌 Why are electric wires covered in plastic? (a) plastic is a conductor (b) plastic is an insulator (c) to make them heavy (d) plastic makes current
29. 29.Which of these is an output? (a) a sound sensor (b) an LED (c) a light sensor (d) a motion sensor
30. 30.🧩 Which part changes electrical energy into movement? (a) a resistor (b) a fuse (c) a motor (d) an LED
31. 31.🔌 Is a push button an input or an output for a microcontroller? (a) output (b) input
32. 32.⏱️ loop forever { LED ON; wait 600 ms; LED OFF; wait 400 ms }
    How many times does the LED blink in 9 seconds?
33. 33.⚡ Which tiny particles drift along a metal wire to carry the current? (a) water drops (b) dust particles (c) photons (d) electrons
34. 34.🌐 What does IoT stand for? (a) Inside of Toys (b) Internet of Talk (c) Input of Tools (d) Internet of Things
35. 35.🔋 Cells joined + to − in a row (series) give … (a) no voltage (b) the same voltage (c) a smaller voltage (d) a bigger voltage
36. 36.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
37. 37.🌈 In the resistor colour code, which number does violet stand for?
38. 38.💡 2 identical bulbs are joined in parallel across a 4.5 V battery (ideal wires). How many volts does each bulb get? =
39. 39.Which of these is an input? (a) a keypad (b) a small display (c) a motor (d) a buzzer
40. 40.🔺 A current of 2.5 A flows when 50 V is joined across a resistor. What is its resistance (in ohms)?

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