Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 655 · 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.🔍 Which sensor would you use to close a window in rain? (a) a sound sensor (b) a temperature sensor (c) a rain sensor (d) a light sensor
2. 2.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a wooden stick across the gap. Does the bulb glow? (a) No (b) Yes
3. 3.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
4. 4.🔍 An object is 170 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
5. 5.🔋 6 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
6. 6.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an LED lamp (c) an oil lamp (d) a candle
7. 7.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V + I (d) P = V × I
8. 8.⚡ A 6 W device works on 12 V. What current does it take (in amperes)? =
9. 9.True or false: “used in house wiring” is true of a series circuit. (a) False (b) True
10. 10.🔁 What does a variable do in a program? (a) measures light (b) stores a value (c) joins two wires (d) blinks an LED
11. 11.🔁 count = 6
    repeat 9 times { count = count + 9 }
    What is count at the end?
12. 12.🤖 Microcontroller or laptop: which one has a built-in keyboard? (a) microcontroller (b) laptop
13. 13.🔌 Why are electric wires covered in plastic? (a) to make them heavy (b) plastic is an insulator (c) plastic is a conductor (d) plastic makes current
14. 14.🔺 A current of 25 mA flows when 8.25 V is joined across a resistor. What is its resistance (in ohms)?
15. 15.🔋 On a cell, does “usually the black wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
16. 16.🤖 if (sound > 70) { red LED ON } else { green LED ON }
    The sound sensor reads 76. What happens? (a) red LED ON (b) green LED ON
17. 17.🔐 Is it a good or a risky habit to post your live location? (a) good habit (b) risky habit
18. 18.✏️ In a circuit diagram, which part is drawn as triangle, bar and arrows? (a) wire (b) resistor (c) switch (d) LED
19. 19.🔁 count = 1
    repeat 5 times { count = count + 5 }
    What is count at the end?
20. 20.🔍 Which is the odd one out? (a) use a cable with cuts (b) poke things in a socket (c) take cells out after use (d) use mains for a project
21. 21.🔌 Which part of a screwdriver should an electrician hold? (a) the metal tip (b) the bare end (c) the plastic handle (d) the steel shaft
22. 22.🔐 Is it a good or a risky habit to accept every permission? (a) risky habit (b) good habit
23. 23.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the if part (b) both parts (c) neither part (d) the else part
24. 24.💡 4 identical bulbs are joined in series with a 6 V battery (ideal wires). How many volts does each bulb get? =
25. 25.🔁 What does “count = count + 1” do? (a) prints 1 (b) takes 1 away (c) adds 1 to count (d) sets count to 1
26. 26.True or false: to throw cells in a fire is safe. (a) True (b) False
27. 27.💡 A battery lights 2 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) brighter (b) the same (c) dimmer
28. 28.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = I ÷ V (c) R = V × I (d) R = V ÷ I
29. 29.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
30. 30.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
31. 31.What does a potentiometer do? (a) smooths a wobbly supply (b) limits the current (c) makes a beeping sound (d) is a resistance knob
32. 32.True or false: “one out, the rest glow” is true of a series circuit. (a) True (b) False
33. 33.🤖 if (sound > 60) { red LED ON } else { green LED ON }
    The sound sensor reads 71. What happens? (a) green LED ON (b) red LED ON
34. 34.🧩 A capacitor in a circuit can … (a) measure heat (b) store charge briefly (c) spin a wheel (d) make light
35. 35.Which of these is the output? (a) check if temp > 30 (b) a button press (c) a buzzer beeps (d) a soil moisture reading
36. 36.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = I ÷ R (c) V = I × R (d) V = R ÷ I
37. 37.Which of these is not safe? (a) fly a kite near wires (b) stop if a part gets hot (c) dry your hands first (d) keep drinks far away
38. 38.💡 3 identical bulbs are joined in series with a battery and a closed switch on the main wire. All the bulbs are in place. How many bulbs glow?
39. 39.Which of these is not safe? (a) stay away from pylons (b) use small battery cells (c) build with an adult near (d) touch a switch when wet
40. 40.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) by Wi-Fi (b) in parallel (c) not joined (d) in series

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