Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 687 · 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.🔋 3 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)? =
2. 2.✏️ In a circuit diagram, which part is drawn as a straight line? (a) cell (b) battery (c) wire (d) bulb
3. 3.💡 An LED is joined to a 3 V battery through a 470 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) does not light (b) may burn out (c) lights up
4. 4.⏱️ loop forever { LED ON; wait 50 ms; LED OFF; wait 900 ms }
   How many milliseconds does one blink (ON + OFF) take?
5. 5.🌈 Which band is read first on a resistor? (a) any band (b) the gold band (c) the widest gap (d) the one nearest an end
6. 6.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
7. 7.Which of these is safe? (a) fly kites in open fields (b) fly a kite near wires (c) throw cells in a fire (d) poke things in a socket
8. 8.🌐 What does IoT stand for? (a) Inside of Toys (b) Input of Tools (c) Internet of Talk (d) Internet of Things
9. 9.🔍 Which is the odd one out? (a) an iron nail (b) a metal paper clip (c) a ceramic cup (d) a copper wire
10. 10.🤖 Does a bicycle bell usually have a microcontroller inside? (a) No (b) Yes
11. 11.💡 3 identical bulbs are joined in parallel across a 12 V battery (ideal wires). How many volts does each bulb get? =
12. 12.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) + (positive) (b) − (negative)
13. 13.What does a tilt switch do? (a) slides side to side (b) flips up or down (c) closes near a magnet (d) closes when tipped over
14. 14.🔁 count = 8
    repeat 8 times { count = count + 2 }
    What is count at the end?
15. 15.🔺 A 12 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
16. 16.🧮 Resistors of 22 Ω, 330 Ω, 100 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
17. 17.🔺 A current of 0.1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
18. 18.💡 A battery lights 5 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
19. 19.💡 An LED is joined to a 5 V battery through a 220 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) lights up (b) does not light (c) may burn out
20. 20.What does a push button do? (a) flips up or down (b) works only while pressed (c) closes near a magnet (d) closes when tipped over
21. 21.⏱️ repeat 2 times { buzzer ON; wait 600 ms; buzzer OFF; wait 100 ms }
    How many milliseconds does this take in all?
22. 22.🌐 Is a Wi-Fi smart plug an IoT device? (a) not an IoT device (b) an IoT device
23. 23.🔋 How many 1.2 V cells must be joined in series to give 4.8 V?
24. 24.💡 6 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 1 is taken out of its holder. How many bulbs glow?
25. 25.True or false: on an LED, the shorter leg is the cathode (−). (a) True (b) False
26. 26.🤖 Microcontroller or laptop: which one has a built-in keyboard? (a) laptop (b) microcontroller
27. 27.🧩 Which component is a resistance knob? (a) potentiometer (b) thermistor (c) resistor (d) capacitor
28. 28.🤖 if (temperature > 33) { 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
29. 29.🔺 A current of 2.5 A flows when 12.5 V is joined across a resistor. What is its resistance (in ohms)?
30. 30.Which of these is not an IoT device? (a) a fitness band with app (b) a plain wall switch (c) a smart energy meter (d) a Wi-Fi weather station
31. 31.🔗 Series or parallel circuit: “one out, the rest glow”? (a) series (b) parallel
32. 32.🔌 A gap of dry air between two wires acts as … (a) a cell (b) an insulator (c) a conductor (d) a switch that is ON
33. 33.True or false: to touch a switch when wet is not safe. (a) False (b) True
34. 34.🔺 A 3.3 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
35. 35.🔍 Which sensor would you use to warn of a gas leak? (a) a distance sensor (b) a sound sensor (c) a rain sensor (d) a gas sensor
36. 36.🔁 x = 4
    repeat 3 times { x = x × 2 }
    What is x at the end?
37. 37.🧾 A family uses 120 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
38. 38.🔢 To get a sensor reading onto a phone, which comes first: “the sensor measures” or “it is sent by Wi-Fi”? (a) it is sent by Wi-Fi (b) the sensor measures
39. 39.🌈 A resistor has the colour bands orange, brown, yellow. What is its value in kilo-ohms (kΩ)? =
40. 40.⚡ A device works on 1.5 V and takes 2 A. What is its power (in watts)? =

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