Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 353 · 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.🌐 How does a home IoT device usually send its data to the app? (a) by shouting (b) by post (c) through a candle (d) over Wi-Fi
2. 2.Which of these is safe? (a) use small battery cells (b) use a cable with cuts (c) climb an electric pole (d) touch a switch when wet
3. 3.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
4. 4.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
   set pin 8 HIGH
   set pin 8 HIGH
   set pin 7 LOW
   set pin 7 LOW
   Is the LED ON or OFF at the end? (a) ON (b) OFF
5. 5.✏️ In a circuit diagram, which part is drawn as two or more cell symbols? (a) capacitor (b) LED (c) junction (d) battery
6. 6.True or false: on an LED, the shorter leg is the anode (+). (a) True (b) False
7. 7.Which of these is true of a series circuit? (a) one out, the rest glow (b) many paths for current (c) used in house wiring (d) a single current path
8. 8.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. A gap in one wire is bridged by a plastic ruler. Does the bulb glow? (a) Yes (b) No
9. 9.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 1000 ms }
   How many milliseconds does one blink (ON + OFF) take?
10. 10.Which of these means the circuit is closed? (a) a wire is cut (b) the switch is ON (c) the switch is OFF (d) a wire has come loose
11. 11.⚠️ Why must we never touch switches with wet hands? (a) water makes it cold (b) it spoils the paint (c) it is just untidy (d) water carries current
12. 12.⏱️ repeat 3 times { buzzer ON; wait 400 ms; buzzer OFF; wait 700 ms }
    How many milliseconds does this take in all?
13. 13.What does a tilt switch do? (a) stays where you flip it (b) flips up or down (c) closes when tipped over (d) works only while pressed
14. 14.🔐 Privacy for a smart device means controlling … (a) how loud it beeps (b) who can see your data (c) its colour (d) its battery size
15. 15.🧮 A 6.5 V battery is joined to 3 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
16. 16.True or false: to stay away from pylons is safe. (a) True (b) False
17. 17.🔺 A current of 0.1 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
18. 18.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
19. 19.Which of these is a conductor? (a) a dry cork (b) a copper wire (c) a rubber band (d) a glass marble
20. 20.🔋 Does a washing machine give electricity or use electricity? (a) gives electricity (b) uses electricity
21. 21.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire has come loose (c) the loop is complete (d) the switch is OFF
22. 22.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
23. 23.True or false: to dry your hands first is not safe. (a) False (b) True
24. 24.🔍 Which is the odd one out? (a) a steel spoon (b) a dry cork (c) a rubber band (d) a paper strip
25. 25.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
26. 26.💡 Why does an LED need a resistor in series? (a) to make it brighter (b) to store charge (c) to change its colour (d) to limit the current
27. 27.Which of these uses electricity? (a) a power station (b) a computer (c) a cell (d) a generator
28. 28.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
29. 29.What does a toggle switch do? (a) works only while pressed (b) springs back when let go (c) stays where you flip it (d) closes near a magnet
30. 30.True or false: to measure classroom noise, use a soil moisture sensor. (a) True (b) False
31. 31.What does the phone app do? (a) measures the real world (b) reads values, decides (c) shows data to you (d) stores data online
32. 32.🤖 What is a microcontroller? (a) a type of battery (b) a big desktop computer (c) a computer on one chip (d) a kind of bulb
33. 33.Which of these saves electricity? (a) leave fridge door open (b) run fans in empty rooms (c) use daylight to read (d) leave the TV on standby
34. 34.🔺 A current of 10 mA flows when 3.3 V is joined across a resistor. What is its resistance (in ohms)?
35. 35.Which of these is not safe? (a) keep drinks far away (b) fly a kite near wires (c) build with an adult near (d) take cells out after use
36. 36.🔘 A cell and a bulb are joined to 3 side-by-side paths with one switch on each path — A, B and C (parallel). A is OFF, B is ON and C is OFF. Does the bulb glow? (a) Yes (b) No
37. 37.🧾 A family uses 20 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
38. 38.💡 What does LED stand for? (a) low energy device (b) light energy dial (c) large electric dial (d) light-emitting diode
39. 39.🤖 When the main loop of a microcontroller program ends, what happens? (a) it stops forever (b) it deletes itself (c) the board breaks (d) it starts again
40. 40.🤖 if (distance < 10) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 17 cm. What happens? (a) buzzer is silent (b) buzzer beeps

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