Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 547 · 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 50 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
2. 2.True or false: a transistor boosts a small signal. (a) False (b) True
3. 3.🤖 “if (A AND B)” is true when … (a) both A and B are true (b) only B is true (c) only A is true (d) both are false
4. 4.⏱️ loop forever { LED ON; wait 350 ms; LED OFF; wait 150 ms }
   How many times does the LED blink in 2 seconds?
5. 5.🔺 A current of 10 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
6. 6.⚡ Power tells us … (a) the colour of light (b) the size of a cell (c) energy used each second (d) the length of a wire
7. 7.True or false: to use small battery cells is not safe. (a) True (b) False
8. 8.🔍 Which is the odd one out? (a) a glass marble (b) a ceramic cup (c) a wooden stick (d) a steel coin
9. 9.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
10. 10.🔌 Is a paper strip a conductor or an insulator? (a) an insulator (b) a conductor
11. 11.💡 3 identical bulbs are joined in parallel across a 3 V battery (ideal wires). How many volts does each bulb get? =
12. 12.🔁 repeat 4 times { repeat 6 times { beep } }
    How many beeps are there?
13. 13.⚡ A device works on 24 V and takes 1.5 A. What is its power (in watts)? =
14. 14.📏 How many ohms (Ω) is 2.1 kΩ?
15. 15.🔍 Which is the odd one out? (a) a pencil sharpener (b) a Wi-Fi doorbell camera (c) a paper calendar (d) a plain table fan
16. 16.🔋 8 identical 1.5 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
17. 17.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) a wire has come loose (d) the loop is complete
18. 18.💡 What does LED stand for? (a) light energy dial (b) light-emitting diode (c) large electric dial (d) low energy device
19. 19.What does a resistor do? (a) has coloured bands (b) blows if current is high (c) senses how hot it is (d) boosts a small signal
20. 20.🔋 5 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
21. 21.🧾 A family uses 20 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
22. 22.🔋 On a cell, does “the flat end” mean the + end or the − end? (a) + (positive) (b) − (negative)
23. 23.🧮 A 3.5 V battery is joined to 4 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
24. 24.🤖 if (temperature > 36) { show “Hot” } else if (temperature > 25) { show “Warm” } else { show “Cool” }
    The temperature is 35 °C. What is shown? (a) Cool (b) Hot (c) Warm
25. 25.🔌 Which metal is used for most electric wires at home? (a) plastic (b) rubber (c) copper (d) glass
26. 26.Which of these wastes electricity? (a) run fans in empty rooms (b) switch off empty rooms (c) use daylight to read (d) unplug idle chargers
27. 27.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they get dimmer (b) they keep glowing (c) they all go out (d) they explode
28. 28.Which of these is not safe? (a) build with an adult near (b) dry your hands first (c) throw cells in a fire (d) use small battery cells
29. 29.🔋 2 identical 2 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
30. 30.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 72 Ω resistor? (a) grey-red-black (b) violet-red-brown (c) violet-red-black (d) red-violet-black
31. 31.💡 An LED is joined to a 3 V battery through a 470 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) does not light (b) may burn out (c) lights up
32. 32.🌐 In an IoT system, which part shows data to you? (a) Wi-Fi (b) actuator (c) phone app (d) cloud server
33. 33.⏱️ How many milliseconds is a wait of 0.3 seconds?
34. 34.🗺️ 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
35. 35.True or false: a buzzer smooths a wobbly supply. (a) False (b) True
36. 36.🔁 x = 4
    repeat 5 times { x = x × 2 }
    What is x at the end?
37. 37.⏱️ loop forever { LED ON; wait 50 ms; LED OFF; wait 150 ms }
    How many times does the LED blink in 1 second?
38. 38.✏️ In a circuit diagram, which part is drawn as a circle with A inside? (a) voltmeter (b) bulb (c) junction (d) ammeter
39. 39.⚡ Which tiny particles drift along a metal wire to carry the current? (a) water drops (b) photons (c) electrons (d) dust particles
40. 40.⚠️ Is it safe to poke things in a socket? (a) not safe (b) safe

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