Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 344 · 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 20 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
2. 2.⏱️ repeat 10 times { buzzer ON; wait 600 ms; buzzer OFF; wait 500 ms }
   How many milliseconds does this take in all?
3. 3.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
4. 4.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 48 Ω resistor? (a) yellow-grey-black (b) grey-yellow-black (c) yellow-grey-brown (d) green-grey-black
5. 5.🔺 A current of 1.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
6. 6.Which of these is an IoT device? (a) a battery torch (b) a plain wall switch (c) a plain table fan (d) a Wi-Fi doorbell camera
7. 7.🤖 Does a spinning top usually have a microcontroller inside? (a) Yes (b) No
8. 8.📶 On a 5 V board, a pin set HIGH gives about … (a) 50 V (b) 230 V (c) 5 V (d) 0 V
9. 9.🔢 To run one loop of a plant-watering program, which is the FIRST step? (a) read the soil sensor (b) wait a few seconds (c) switch the pump on/off (d) compare with the limit
10. 10.Which drawing is the symbol for a cell? (a) a long and a short line (b) a straight line (c) a small empty box (d) two or more cell symbols
11. 11.🔁 count = 1
    while (count < 29) { count = count + 4 }
    How many times does the loop run?
12. 12.🗺️ In an input → process → output plan, is “compare with a limit” the input, the process or the output? (a) output (b) input (c) process
13. 13.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
14. 14.True or false: “many paths for current” is true of a series circuit. (a) True (b) False
15. 15.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
16. 16.🌈 A resistor has the colour bands white, brown, brown. What is its value (in ohms)?
17. 17.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
18. 18.🔺 A 2 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
19. 19.⚠️ Someone is getting a shock and is still touching a wire. What should you do? (a) pour water on them (b) wait and watch (c) pull them by the hand (d) shout for an adult
20. 20.🔘 A cell, a bulb and switches A, B, C and D are joined one after another in a single loop (series). A is ON, B is ON, C is ON and D is ON. Does the bulb glow? (a) No (b) Yes
21. 21.🔁 count = 2
    while (count < 12) { count = count + 5 }
    How many times does the loop run?
22. 22.🌐 A weather station sends one reading every 60 seconds. How many readings does it send in 9 minutes?
23. 23.🔗 Series or parallel circuit: “one out, the rest glow”? (a) series (b) parallel
24. 24.🔺 A current of 1.5 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
25. 25.⚡ A bicycle dynamo changes which kind of energy into electricity? (a) chemical energy (b) sound energy (c) movement energy (d) light energy
26. 26.🔍 Which is the odd one out? (a) open a phone charger (b) climb an electric pole (c) poke things in a socket (d) dry your hands first
27. 27.Which of these is a good habit? (a) share camera links (b) install software updates (c) ignore update messages (d) accept every permission
28. 28.⚡ A device works on 12 V and takes 3 A. What is its power (in watts)? =
29. 29.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) − (negative) (b) + (positive)
30. 30.Which job is done by the power LED? (a) brings power and code (b) connect sensors and LEDs (c) keeps the voltage steady (d) shows the board is on
31. 31.Which of these is true of a series circuit? (a) many paths for current (b) used in house wiring (c) a break stops every bulb (d) each gets the full volts
32. 32.True or false: on an LED, the longer leg is the cathode (−). (a) False (b) True
33. 33.💡 2 identical bulbs are joined in parallel across a 12 V battery (ideal wires). How many volts does each bulb get? =
34. 34.True or false: “a break stops every bulb” is true of a parallel circuit. (a) False (b) True
35. 35.True or false: to leave the TV on standby wastes electricity. (a) False (b) True
36. 36.🗺️ In an input → process → output plan, is “check if temp > 30” the input, the process or the output? (a) output (b) input (c) process
37. 37.True or false: to iron one shirt at a time saves electricity. (a) False (b) True
38. 38.True or false: a school bell mainly gives out heat. (a) False (b) True
39. 39.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 HIGH
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) OFF (b) ON
40. 40.🌈 In the resistor colour code, which number does brown stand for?

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