Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 721 · 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.🔺 A current of 40 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
2. 2.🔁 count = 10
   repeat 9 times { count = count + 3 }
   What is count at the end?
3. 3.🔍 Which is the odd one out? (a) a table fan (b) a mixer grinder (c) a traffic signal (d) an exhaust fan
4. 4.🔍 Which is the odd one out? (a) a mixer grinder (b) a siren (c) a table fan (d) an electric drill
5. 5.🔍 Which is the odd one out? (a) turn off unused gadgets (b) share only needed data (c) ignore update messages (d) set a strong password
6. 6.🔘 What does a switch do in a circuit? (a) stores current (b) makes electricity (c) opens or closes the loop (d) changes the voltage
7. 7.🔢 To get a sensor reading onto a phone, which comes first: “the app shows it” or “the cloud stores it”? (a) the cloud stores it (b) the app shows it
8. 8.🌈 A resistor has the colour bands white, violet, brown. What is its value (in ohms)?
9. 9.✏️ In a circuit diagram, which part is drawn as a circle with an X in it? (a) LED (b) resistor (c) bulb (d) cell
10. 10.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) bigger (c) stay the same (d) smaller
11. 11.🤖 Where does the board keep its program when the power is off? (a) the USB cable (b) the resistor (c) the power LED (d) flash memory
12. 12.🔘 A cell and a bulb are joined to two side-by-side paths: path 1 has switches A and B one after another, path 2 has switch C. A is ON, B is ON and C is OFF. Does the bulb glow? (a) Yes (b) No
13. 13.What does an LDR do? (a) makes things spin (b) senses how bright it is (c) stores a little charge (d) turns a fan or wheels
14. 14.🔍 An object is 136 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
15. 15.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) use LED lamps (c) run fans in empty rooms (d) close the fridge quickly
16. 16.🔁 repeat 5 times { repeat 3 times { beep } }
    How many beeps are there?
17. 17.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
18. 18.True or false: a long and a short line is the symbol for an ammeter. (a) True (b) False
19. 19.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
20. 20.🤖 How does a new program get onto a microcontroller board? (a) typed on the chip (b) sent by sound (c) drawn with a pen (d) uploaded over USB
21. 21.🔌 Is a motion sensor an input or an output for a microcontroller? (a) output (b) input
22. 22.🤖 if (sound > 60) { red LED ON } else { green LED ON }
    The sound sensor reads 46. What happens? (a) red LED ON (b) green LED ON
23. 23.🔌 Is a brass key a conductor or an insulator? (a) an insulator (b) a conductor
24. 24.💡 5 identical bulbs are joined in parallel (each on its own side-by-side path) with a battery and a closed switch on the main wire. Bulb 3 is taken out of its holder. How many bulbs glow?
25. 25.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
26. 26.True or false: to take cells out after use is safe. (a) True (b) False
27. 27.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 2700 Ω resistor? (a) red-violet-brown (b) red-violet-red (c) red-violet-orange (d) violet-red-red
28. 28.💡 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 8 LOW
    set pin 8 HIGH
    Is the LED ON or OFF at the end? (a) ON (b) OFF
29. 29.Which of these mainly makes sound? (a) a tube light (b) a school bell (c) an electric iron (d) a torch
30. 30.🧮 Three equal 75 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
31. 31.Which of these is an insulator? (a) an iron nail (b) a brass key (c) a dry cork (d) a graphite rod
32. 32.True or false: an iron nail is an insulator. (a) True (b) False
33. 33.True or false: a toy robot usually has a microcontroller inside. (a) False (b) True
34. 34.⚡ What does an exhaust fan mainly change electricity into? (a) heat (b) light (c) movement (d) sound
35. 35.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the glass (c) the base (d) the filament
36. 36.🌈 In the resistor colour code, which number does orange stand for?
37. 37.True or false: a line lifted at a gap is the symbol for a switch. (a) False (b) True
38. 38.True or false: to dry your hands first is not safe. (a) False (b) True
39. 39.🤖 if (temperature > 32) { show “Hot” } else if (temperature > 24) { show “Warm” } else { show “Cool” }
    The temperature is 28 °C. What is shown? (a) Warm (b) Cool (c) Hot
40. 40.⏱️ How many milliseconds are in 1 second? (a) 100 (b) 1000 (c) 60 (d) 10

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