Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 297 · 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 resistor has the colour bands orange, orange, red. What is its value in kilo-ohms (kΩ)? =
2. 2.🔐 Is it a good or a risky habit to share only needed data? (a) good habit (b) risky habit
3. 3.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
4. 4.🔺 A 4 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
5. 5.🔘 Which kind of switch stays where you flip it? (a) a push button (b) a slide switch (c) a tilt switch (d) a toggle switch
6. 6.True or false: on a cell, “the flat end” means the − (negative) end. (a) True (b) False
7. 7.🔍 Which is the odd one out? (a) a push button (b) a motor (c) a buzzer (d) a small display
8. 8.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = V ÷ I (c) R = I ÷ V (d) R = V × I
9. 9.🌐 Each reading a sensor sends is 50 bytes. How many bytes do 60 readings take?
10. 10.⚡ A 2.25 W device works on 9 V. What current does it take (in amperes)? =
11. 11.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
12. 12.Which job is done by the USB port? (a) connect sensors and LEDs (b) keeps the voltage steady (c) restarts the program (d) brings power and code
13. 13.🔘 What does a switch do in a circuit? (a) changes the voltage (b) makes electricity (c) stores current (d) opens or closes the loop
14. 14.🌐 How does a home IoT device usually send its data to the app? (a) by post (b) through a candle (c) over Wi-Fi (d) by shouting
15. 15.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by an iron nail. Does the bulb glow? (a) Yes (b) No
16. 16.🌈 In the resistor colour code, which number does orange stand for?
17. 17.🔋 What is a battery? (a) two or more cells joined (b) a switch with a lid (c) a kind of bulb (d) one single wire
18. 18.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 50 ms }
    How many times does the LED blink in 8 seconds?
19. 19.Which of these is an IoT device? (a) a fitness band with app (b) a plain table fan (c) a paper calendar (d) a wind-up clock
20. 20.⚠️ About how many volts do home sockets in India supply? (a) 12 V (b) 230 V (c) 1.5 V (d) 9 V
21. 21.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
22. 22.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
23. 23.True or false: “check if temp > 30” is the input. (a) True (b) False
24. 24.🔺 A 30 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
25. 25.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it makes a sound (c) it does not light (d) it changes colour
26. 26.🧩 A capacitor in a circuit can … (a) spin a wheel (b) measure heat (c) store charge briefly (d) make light
27. 27.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 7 LOW
    set pin 8 LOW
    set pin 7 HIGH
    Is the LED ON or OFF at the end? (a) OFF (b) ON
28. 28.True or false: a woollen thread is a conductor. (a) False (b) True
29. 29.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
30. 30.💡 Why is house wiring done in parallel? (a) so all go off together (b) to make bulbs dim (c) each gets full voltage (d) to save copper only
31. 31.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 50 % (c) 0 % (d) 25 %
32. 32.🔍 Which is the odd one out? (a) a cotton thread (b) a brass key (c) a metal paper clip (d) a steel coin
33. 33.🔁 x = 1
    repeat 2 times { x = x × 2 }
    What is x at the end?
34. 34.⏱️ A program says “wait 1750 ms”. How many seconds is that? =
35. 35.True or false: a capacitor limits the current. (a) False (b) True
36. 36.⏱️ What does “wait 500 ms” do? (a) pauses for half a second (b) turns the LED off (c) blinks 500 times (d) waits 500 seconds
37. 37.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 7 HIGH
    set pin 8 HIGH
    Is the LED ON or OFF at the end? (a) ON (b) OFF
38. 38.🤖 if (temperature > 37) { show “Hot” } else if (temperature > 19) { show “Warm” } else { show “Cool” }
    The temperature is 43 °C. What is shown? (a) Warm (b) Cool (c) Hot
39. 39.🔗 Series or parallel circuit: “each gets the full volts”? (a) series (b) parallel
40. 40.🔋 A 9 V battery and one 1.5 V cell are joined in series, all facing the same way. What is the total voltage (in volts)? =

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