Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 653 · 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.🔍 An object is 119 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
2. 2.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
3. 3.⚡ Power tells us … (a) the colour of light (b) energy used each second (c) the size of a cell (d) the length of a wire
4. 4.What does a push button do? (a) springs back when let go (b) closes near a magnet (c) slides side to side (d) stays where you flip it
5. 5.🔁 What does “count = count + 1” do? (a) adds 1 to count (b) prints 1 (c) sets count to 1 (d) takes 1 away
6. 6.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
7. 7.🔺 A current of 40 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
8. 8.True or false: a woollen thread is a conductor. (a) True (b) False
9. 9.🔍 Which is the odd one out? (a) ignore update messages (b) share the Wi-Fi key (c) share camera links (d) read app permissions
10. 10.⚡ A device works on 6 V and takes 0.2 A. What is its power (in watts)? =
11. 11.🌐 Is a pencil sharpener an IoT device? (a) not an IoT device (b) an IoT device
12. 12.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V + I (c) P = I ÷ V (d) P = V × I
13. 13.🔍 Which is the odd one out? (a) build with an adult near (b) poke things in a socket (c) climb an electric pole (d) throw cells in a fire
14. 14.Which of these is a risky habit? (a) install software updates (b) keep factory passwords (c) read app permissions (d) cover unused cameras
15. 15.✏️ Why do engineers draw circuits with symbols? (a) symbols are heavier (b) to make it colourful (c) to hide the circuit (d) quick and clear for all
16. 16.🔁 repeat 3 times { repeat 5 times { beep } }
    How many beeps are there?
17. 17.🤖 Microcontroller or laptop: which one needs much more power? (a) microcontroller (b) laptop
18. 18.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
19. 19.Which job is done by the USB port? (a) keeps the voltage steady (b) brings power and code (c) shows the board is on (d) connect sensors and LEDs
20. 20.True or false: a laptop has no screen of its own. (a) True (b) False
21. 21.True or false: a diode lets current go one way. (a) False (b) True
22. 22.🔍 Which is the odd one out? (a) a battery torch (b) a plain table fan (c) a pencil sharpener (d) a Wi-Fi doorbell camera
23. 23.🌈 A resistor has the colour bands orange, red, red. What is its value in kilo-ohms (kΩ)? =
24. 24.🔐 Is it a good or a risky habit to cover unused cameras? (a) risky habit (b) good habit
25. 25.What does a diode do? (a) glows using little power (b) lets current go one way (c) turns a fan or wheels (d) stores a little charge
26. 26.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
27. 27.🔁 total = 0
    for i = 1 to 4 { total = total + i }
    What is total at the end?
28. 28.🧩 Which component lets current go one way? (a) LED (b) buzzer (c) fuse (d) diode
29. 29.Which of these gives us electricity? (a) an air conditioner (b) a computer (c) a water pump (d) a power station
30. 30.💡 3 identical bulbs are in parallel and each one takes 1.5 A. What total current (in amperes) comes from the battery? =
31. 31.🔍 Which is the odd one out? (a) close the fridge quickly (b) run fans in empty rooms (c) set the AC to 24 °C (d) switch off empty rooms
32. 32.🤖 if (light < 300 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 50 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
33. 33.What does an LDR do? (a) boosts a small signal (b) makes things spin (c) turns a fan or wheels (d) senses how bright it is
34. 34.Which of these mainly makes movement? (a) a doorbell (b) a traffic signal (c) an exhaust fan (d) a room heater
35. 35.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they get dimmer (b) they all go out (c) they explode (d) they keep glowing
36. 36.🔺 An 8 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
37. 37.🔍 Which is the odd one out? (a) use LED lamps (b) use old filament bulbs (c) unplug idle chargers (d) switch off empty rooms
38. 38.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
39. 39.🔺 A current of 50 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
40. 40.True or false: to use LED lamps wastes electricity. (a) False (b) True

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