Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 372 · 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 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 cotton thread. Does the bulb glow? (a) No (b) Yes
2. 2.⚡ A cell changes stored chemical energy into which kind of energy? (a) electrical energy (b) wind energy (c) sound energy (d) nuclear energy
3. 3.Which of these is an IoT device? (a) a Wi-Fi doorbell camera (b) a plain wall switch (c) a plain table fan (d) a battery torch
4. 4.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to limit the current (c) to make it brighter (d) to store charge
5. 5.🔺 A 0.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
6. 6.🧩 Which component senses how bright it is? (a) resistor (b) motor (c) diode (d) LDR
7. 7.🔘 When a switch is ON, the circuit is … (a) broken (b) closed (c) cut (d) open
8. 8.⚡ A 3 W device works on 1.5 V. What current does it take (in amperes)? =
9. 9.🔗 Series or parallel circuit: “a single current path”? (a) series (b) parallel
10. 10.🔢 To get a sensor reading onto a phone, which comes first: “it is sent by Wi-Fi” or “the sensor measures”? (a) the sensor measures (b) it is sent by Wi-Fi
11. 11.🔘 A bulb and a cell are joined through 4 switches one after another in a single loop (series). What is the smallest number of switches that must be ON to light the bulb?
12. 12.⚡ A 0.75 W device works on 3 V. What current does it take (in amperes)? =
13. 13.True or false: to stop if a part gets hot is not safe. (a) True (b) False
14. 14.🔐 Why install updates on IoT devices? (a) they delete the Wi-Fi (b) they change the colour (c) they make it heavier (d) they fix security holes
15. 15.Which of these usually has a microcontroller inside? (a) a toy robot (b) a candle (c) a wind-up toy (d) a spinning top
16. 16.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. 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
17. 17.🔺 A current of 0.2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
18. 18.🔁 What does a variable do in a program? (a) joins two wires (b) blinks an LED (c) stores a value (d) measures light
19. 19.🔍 Which is the odd one out? (a) a wind-up clock (b) a plain wall switch (c) a pencil sharpener (d) an app-controlled bulb
20. 20.🔍 Which sensor would you use to switch on lamps at dusk? (a) a light sensor (b) a distance sensor (c) a soil moisture sensor (d) a motion sensor
21. 21.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
22. 22.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
23. 23.Which job is done by the USB port? (a) connect sensors and LEDs (b) runs the program (c) shows the board is on (d) brings power and code
24. 24.🔍 Which is the odd one out? (a) touch a fallen wire (b) climb an electric pole (c) poke things in a socket (d) stay away from pylons
25. 25.True or false: voltage is measured in volts (V). (a) True (b) False
26. 26.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a glass marble across the gap. Does the bulb glow? (a) No (b) Yes
27. 27.🔍 Which is the odd one out? (a) a temperature sensor (b) a sound sensor (c) a water pump (d) a turning knob
28. 28.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
29. 29.What does a toggle switch do? (a) springs back when let go (b) stays where you flip it (c) closes when tipped over (d) closes near a magnet
30. 30.What does a push button do? (a) stays where you flip it (b) closes when tipped over (c) works only while pressed (d) flips up or down
31. 31.✏️ In a cell symbol, which line is the + terminal? (a) the shorter line (b) neither line (c) both lines (d) the longer line
32. 32.🔍 Which is the odd one out? (a) a glass marble (b) a rubber band (c) a cotton thread (d) a steel coin
33. 33.True or false: “one bulb out, all go out” is true of a series circuit. (a) False (b) True
34. 34.📏 How many milliamperes (mA) make 1 ampere? (a) 60 (b) 10 (c) 100 (d) 1000
35. 35.⚠️ About how many volts do home sockets in India supply? (a) 12 V (b) 1.5 V (c) 9 V (d) 230 V
36. 36.⚙️ Which actuator would you use to show the temperature? (a) a pump (b) an LED (c) a display (d) a servo motor
37. 37.🌐 Is a Wi-Fi smart plug an IoT device? (a) not an IoT device (b) an IoT device
38. 38.Which of these saves electricity? (a) switch off empty rooms (b) leave fridge door open (c) iron one shirt at a time (d) use old filament bulbs
39. 39.🔍 A distance sensor sends a sound pulse and hears the echo 9 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
40. 40.🌈 A resistor has the colour bands brown, black, black. What is its value (in ohms)?

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