Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 418 · 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.True or false: to keep factory passwords is a good habit. (a) True (b) False
2. 2.🔍 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?
3. 3.🤖 Where does the board keep its program when the power is off? (a) the USB cable (b) the power LED (c) the resistor (d) flash memory
4. 4.🔍 A distance sensor sends a sound pulse and hears the echo 6 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
5. 5.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 100 ms }
   How many times does the LED blink in 3 seconds?
6. 6.🔺 A 0.4 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
7. 7.🔢 To run one loop of a plant-watering program, which is the LAST step? (a) read the soil sensor (b) compare with the limit (c) wait a few seconds (d) switch the pump on/off
8. 8.🔁 x = 1
   repeat 5 times { x = x × 2 }
   What is x at the end?
9. 9.⚠️ Which power source should children use for electronics projects? (a) an inverter socket (b) a wall socket (c) a mains extension board (d) a small battery pack
10. 10.🌈 A resistor has the colour bands violet, brown, orange. What is its value in kilo-ohms (kΩ)? =
11. 11.🔋 How many volts does one ordinary torch cell give? (a) 0.5 V (b) 230 V (c) 15 V (d) 1.5 V
12. 12.🧩 Which component has coloured bands? (a) motor (b) potentiometer (c) resistor (d) diode
13. 13.🔗 Series or parallel circuit: “used in house wiring”? (a) parallel (b) series
14. 14.🔋 Identical cells side by side (in parallel) give … (a) half the voltage (b) the same voltage (c) double the voltage (d) no voltage
15. 15.🗺️ Before building a project, what should you write down first? (a) the final price (b) the box colour (c) nothing at all (d) inputs and outputs
16. 16.🔗 Series or parallel circuit: “each gets the full volts”? (a) parallel (b) series
17. 17.🧮 Two resistors in parallel give a total that is … (a) their sum (b) always zero (c) less than either one (d) more than either one
18. 18.Which job needs a temperature sensor? (a) keep an incubator warm (b) water a dry plant (c) spot someone walking in (d) open blinds at sunrise
19. 19.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) stay the same (c) zero (d) smaller
20. 20.True or false: a resistor stores a little charge. (a) True (b) False
21. 21.True or false: “a single current path” is true of a series circuit. (a) True (b) False
22. 22.💡 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 8 LOW
    set pin 8 LOW
    Is the LED ON or OFF at the end? (a) OFF (b) ON
23. 23.🔍 Which is the odd one out? (a) a graphite rod (b) a glass marble (c) a safety pin (d) a metal paper clip
24. 24.🌐 In an IoT system, which part carries the data? (a) actuator (b) Wi-Fi (c) sensor (d) microcontroller
25. 25.True or false: to set the AC to 24 °C saves electricity. (a) False (b) True
26. 26.🗺️ In an input → process → output plan, is “a motion sensor signal” the input, the process or the output? (a) output (b) input (c) process
27. 27.True or false: “used in house wiring” is true of a parallel circuit. (a) True (b) False
28. 28.Which of these is a risky habit? (a) share only needed data (b) read app permissions (c) share camera links (d) install software updates
29. 29.🤖 Does a smart watch usually have a microcontroller inside? (a) No (b) Yes
30. 30.True or false: “check if temp > 30” is the input. (a) False (b) True
31. 31.💡 A battery lights 4 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) brighter (b) the same (c) dimmer
32. 32.🌈 A resistor has the colour bands yellow, blue, black. What is its value (in ohms)?
33. 33.⏱️ loop forever { LED ON; wait 1000 ms; LED OFF; wait 450 ms }
    How many milliseconds does one blink (ON + OFF) take?
34. 34.True or false: two or more cell symbols is the symbol for a voltmeter. (a) False (b) True
35. 35.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
36. 36.Which of these is the output? (a) a soil moisture reading (b) count button presses (c) compare with a limit (d) an LED lights up
37. 37.⚙️ What is an actuator? (a) a battery (b) a sensor (c) an output that acts (d) a program
38. 38.🔍 Which is the odd one out? (a) a night lamp (b) a tube light (c) an electric iron (d) a traffic signal
39. 39.True or false: a night lamp mainly makes sound. (a) True (b) False
40. 40.🧮 Five equal 250 Ω resistors are joined in parallel. What is the total resistance (in ohms)?

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