Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 388 · 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.🔁 What must there be for a current to flow? (a) a broken path (b) a complete loop (c) one loose end (d) a plastic gap
2. 2.🔌 Why are electric wires covered in plastic? (a) plastic is an insulator (b) plastic is a conductor (c) to make them heavy (d) plastic makes current
3. 3.🧩 Which component has coloured bands? (a) potentiometer (b) resistor (c) thermistor (d) LDR
4. 4.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) − (negative) (b) + (positive)
5. 5.True or false: a ceramic cup is a conductor. (a) False (b) True
6. 6.💡 A battery lights 4 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) the same (b) dimmer (c) brighter
7. 7.Which of these saves electricity? (a) leave fridge door open (b) use old filament bulbs (c) leave the TV on standby (d) unplug idle chargers
8. 8.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a capacitor (c) a diode (d) a buzzer
9. 9.🔍 Which is the odd one out? (a) climb an electric pole (b) dry your hands first (c) keep drinks far away (d) fly kites in open fields
10. 10.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
11. 11.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the if part (b) both parts (c) the else part (d) neither part
12. 12.True or false: to use daylight to read wastes electricity. (a) False (b) True
13. 13.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 8 hours. How many watt-hours (Wh) are saved?
14. 14.⏱️ repeat 8 times { buzzer ON; wait 100 ms; buzzer OFF; wait 100 ms }
    How many milliseconds does this take in all?
15. 15.🔍 Which is the odd one out? (a) use a cable with cuts (b) touch a switch when wet (c) throw cells in a fire (d) keep drinks far away
16. 16.⏱️ How many milliseconds is a wait of 4.9 seconds?
17. 17.🌈 A resistor has the colour bands orange, green, red. What is its value (in ohms)?
18. 18.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
19. 19.True or false: to use small battery cells is not safe. (a) False (b) True
20. 20.True or false: power is measured in watts (W). (a) True (b) False
21. 21.🔁 repeat 4 times { repeat 3 times { beep } }
    How many beeps are there?
22. 22.🌐 How does a home IoT device usually send its data to the app? (a) by shouting (b) over Wi-Fi (c) by post (d) through a candle
23. 23.🤖 How does a new program get onto a microcontroller board? (a) sent by sound (b) typed on the chip (c) uploaded over USB (d) drawn with a pen
24. 24.🤖 Where does the board keep its program when the power is off? (a) the resistor (b) the USB cable (c) the power LED (d) flash memory
25. 25.Which of these means the circuit is open? (a) all wires are joined (b) the bulb is unscrewed (c) the switch is ON (d) the loop is complete
26. 26.What does an LDR do? (a) makes things spin (b) senses how hot it is (c) turns a fan or wheels (d) senses how bright it is
27. 27.What does a tilt switch do? (a) closes near a magnet (b) springs back when let go (c) flips up or down (d) closes when tipped over
28. 28.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
29. 29.🔍 Which is the odd one out? (a) an alert on the phone (b) the fan starts (c) check if temp > 30 (d) the pump turns on
30. 30.🔍 Which is the odd one out? (a) build with an adult near (b) open a phone charger (c) keep drinks far away (d) dry your hands first
31. 31.True or false: on a cell, “usually the red wire” means the + (positive) end. (a) False (b) True
32. 32.True or false: “one bulb out, all go out” is true of a series circuit. (a) True (b) False
33. 33.🔌 Is a water pump an input or an output for a microcontroller? (a) output (b) input
34. 34.🔁 count = 5
    while (count < 25) { count = count + 4 }
    How many times does the loop run?
35. 35.🌈 A resistor has the colour bands orange, yellow, yellow. What is its value in kilo-ohms (kΩ)? =
36. 36.🌈 In the resistor colour code, which number does brown stand for?
37. 37.🔘 Which kind of switch springs back when let go? (a) a toggle switch (b) a push button (c) a tilt switch (d) a reed switch
38. 38.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 5 % (c) 50 % (d) 0 %
39. 39.🔺 A current of 40 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
40. 40.🧾 A family uses 100 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?

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