Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 612 · 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 red LED (it uses 2 V) is joined with a 200 Ω resistor to a 6 V supply. What current flows (in mA)?
2. 2.What does the microcontroller do? (a) shows data to you (b) measures the real world (c) reads values, decides (d) carries the data
3. 3.🔢 To plan an electronics project, which is the FIRST step? (a) list inputs and outputs (b) test it and fix it (c) draw the circuit diagram (d) pick a problem to solve
4. 4.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
5. 5.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 1 hour. How many watt-hours (Wh) are saved?
6. 6.💡 Why is house wiring done in parallel? (a) so all go off together (b) to make bulbs dim (c) each gets full voltage (d) to save copper only
7. 7.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1000 (b) 1024 (c) 100 (d) 10
8. 8.💡 2 identical bulbs are joined in parallel across a 12 V battery (ideal wires). How many volts does each bulb get? =
9. 9.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) zero (c) bigger (d) stay the same
10. 10.🔦 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 ruler. Does the bulb glow? (a) No (b) Yes
11. 11.🧾 A 200 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
12. 12.🔺 A current of 10 mA flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
13. 13.Which of these is a good habit? (a) share the Wi-Fi key (b) share camera links (c) keep factory passwords (d) log out of shared phones
14. 14.🔁 count = 1
    while (count < 7) { count = count + 3 }
    How many times does the loop run?
15. 15.⏱️ What does “wait 500 ms” do? (a) waits 500 seconds (b) turns the LED off (c) pauses for half a second (d) blinks 500 times
16. 16.✏️ In a circuit diagram, wires are usually drawn as … (a) dotted circles (b) little stars (c) straight lines (d) wavy lines
17. 17.⚙️ Which actuator would you use to show the temperature? (a) a motor (b) a display (c) a servo motor (d) a pump
18. 18.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
19. 19.🔍 Which sensor would you use to spot someone walking in? (a) a motion sensor (b) a temperature sensor (c) a distance sensor (d) a rain sensor
20. 20.🤖 if (distance < 10) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 15 cm. What happens? (a) buzzer is silent (b) buzzer beeps
21. 21.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they all go out (b) they get dimmer (c) they keep glowing (d) they explode
22. 22.🔺 A current of 0.25 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
23. 23.🔐 Is it a good or a risky habit to install software updates? (a) risky habit (b) good habit
24. 24.🔌 Is a glass marble a conductor or an insulator? (a) a conductor (b) an insulator
25. 25.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) by Wi-Fi (b) not joined (c) in series (d) in parallel
26. 26.Which of these means the circuit is closed? (a) a wire is cut (b) all wires are joined (c) the switch is OFF (d) the bulb is unscrewed
27. 27.🔘 Two switches are in series. When does the bulb glow? (a) when either is ON (b) never (c) when both are ON (d) when both are OFF
28. 28.🧮 Resistors of 20 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
29. 29.🧮 Resistors of 220 Ω, 68 Ω, 150 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
30. 30.🧮 A 20 Ω resistor is joined in series with two equal 1000 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
31. 31.💡 4 identical bulbs are joined in parallel (each on its own side-by-side path) with a battery and a closed switch on the main wire. Bulbs 2 and 4 are taken out of their holders. How many bulbs glow?
32. 32.⚡ What does a street light mainly change electricity into? (a) sound (b) heat (c) movement (d) light
33. 33.⚡ A 24 W device works on 24 V. What current does it take (in amperes)? =
34. 34.⏱️ repeat 10 times { buzzer ON; wait 900 ms; buzzer OFF; wait 300 ms }
    How many milliseconds does this take in all?
35. 35.🔢 To run one loop of a plant-watering program, which comes first: “compare with the limit” or “read the soil sensor”? (a) compare with the limit (b) read the soil sensor
36. 36.💡 3 identical bulbs are joined in parallel across a 3 V battery (ideal wires). How many volts does each bulb get? =
37. 37.⏱️ loop forever { LED ON; wait 50 ms; LED OFF; wait 200 ms }
    How many times does the LED blink in 10 seconds?
38. 38.🔘 What does a switch do in a circuit? (a) opens or closes the loop (b) stores current (c) makes electricity (d) changes the voltage
39. 39.🔍 Which sensor would you use to switch on with a clap? (a) a rain sensor (b) a soil moisture sensor (c) a temperature sensor (d) a sound sensor
40. 40.🔗 Series or parallel circuit: “bulbs share the voltage”? (a) series (b) parallel

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