Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 172 · 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.🔐 Is it a good or a risky habit to install software updates? (a) risky habit (b) good habit
2. 2.🔺 A 4 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
3. 3.✏️ In a circuit diagram, which part is drawn as triangle against a bar? (a) diode (b) motor (c) cell (d) capacitor
4. 4.⏱️ How many milliseconds is a wait of 4 seconds?
5. 5.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
6. 6.🔍 Which is the odd one out? (a) leave the TV on standby (b) use old filament bulbs (c) switch off empty rooms (d) iron one shirt at a time
7. 7.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
8. 8.🔘 A bulb and a cell are joined through 4 switches on 4 side-by-side paths, one switch on each path (parallel). What is the smallest number of switches that must be ON to light the bulb?
9. 9.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V × I (d) P = V ÷ I
10. 10.🔌 A gap of dry air between two wires acts as … (a) a switch that is ON (b) a cell (c) a conductor (d) an insulator
11. 11.Which of these is an IoT device? (a) a pencil sharpener (b) a Wi-Fi weather station (c) a battery torch (d) a plain wall switch
12. 12.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a plastic straw across the gap. Does the bulb glow? (a) No (b) Yes
13. 13.⚡ What does a doorbell mainly change electricity into? (a) light (b) heat (c) sound (d) movement
14. 14.True or false: to close the fridge quickly saves electricity. (a) True (b) False
15. 15.True or false: a tube light mainly gives out light. (a) False (b) True
16. 16.⚡ A device works on 5 V and takes 0.2 A. What is its power (in watts)? =
17. 17.✏️ In a circuit diagram, wires are usually drawn as … (a) wavy lines (b) straight lines (c) dotted circles (d) little stars
18. 18.📏 How many kilo-ohms (kΩ) is 2500 Ω? =
19. 19.🌐 In an IoT system, which part acts on a command? (a) actuator (b) Wi-Fi (c) sensor (d) microcontroller
20. 20.Which of these is a good habit? (a) accept every permission (b) ignore update messages (c) keep factory passwords (d) share only needed data
21. 21.💡 4 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?
22. 22.🔍 Which is the odd one out? (a) set up with a parent (b) change default passwords (c) share only needed data (d) share camera links
23. 23.What does the microcontroller do? (a) reads values, decides (b) measures the real world (c) carries the data (d) acts on a command
24. 24.What does a fuse do? (a) makes a beeping sound (b) makes things spin (c) blows if current is high (d) glows using little power
25. 25.True or false: on a cell, “usually the black wire” means the − (negative) end. (a) False (b) True
26. 26.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 7 HIGH
    set pin 8 HIGH
    set pin 8 HIGH
    Is the LED ON or OFF at the end? (a) OFF (b) ON
27. 27.🔍 Which is the odd one out? (a) a motion sensor (b) a motor (c) an LED (d) a water pump
28. 28.Which of these mainly makes sound? (a) a torch (b) a room heater (c) an electric toy car (d) a buzzer
29. 29.🔍 Which sensor would you use to water a dry plant? (a) a soil moisture sensor (b) a rain sensor (c) a light sensor (d) a gas sensor
30. 30.🔺 A 1.2 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
31. 31.🔌 Most metals are good … (a) insulators (b) magnets only (c) batteries (d) conductors
32. 32.🧩 Which component limits the current? (a) diode (b) capacitor (c) buzzer (d) resistor
33. 33.🔍 Which is the odd one out? (a) switch off empty rooms (b) use LED lamps (c) unplug idle chargers (d) run fans in empty rooms
34. 34.🔍 Which is the odd one out? (a) a ceiling fan (b) an electric iron (c) a room heater (d) an electric kettle
35. 35.True or false: to keep factory passwords is a risky habit. (a) True (b) False
36. 36.True or false: “each gets the full volts” is true of a series circuit. (a) True (b) False
37. 37.💡 5 identical bulbs are in parallel and each bulb has its own switch on its path. 1 of the switches is OFF and the rest are ON. How many bulbs glow?
38. 38.🔺 A current of 10 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
39. 39.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the else part (b) both parts (c) the if part (d) neither part
40. 40.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a plastic straw. Does the bulb glow? (a) No (b) Yes

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