Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 740 · 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.🤖 if (distance < 30) { buzzer beeps } else { buzzer is silent }
   The distance sensor reads 28 cm. What happens? (a) buzzer beeps (b) buzzer is silent
2. 2.🤖 Does a plain wall switch usually have a microcontroller inside? (a) No (b) Yes
3. 3.📏 How many kilowatts (kW) is 3700 W? =
4. 4.✏️ In a circuit diagram, which part is drawn as a plain rectangle? (a) resistor (b) bulb (c) ammeter (d) capacitor
5. 5.Which job is done by the power LED? (a) shows the board is on (b) connect sensors and LEDs (c) restarts the program (d) brings power and code
6. 6.🔺 A current of 50 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
7. 7.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
8. 8.🔺 A current of 1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
9. 9.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) it does not matter (c) none (d) only one
10. 10.⏱️ loop forever { LED ON; wait 700 ms; LED OFF; wait 150 ms }
    How many milliseconds does one blink (ON + OFF) take?
11. 11.🔋 What should you do with used-up cells? (a) cut them open (b) give them for recycling (c) bury them in soil (d) throw them in a fire
12. 12.🔁 count = 1
    repeat 5 times { count = count + 4 }
    What is count at the end?
13. 13.🔋 On a cell, does “the shorter symbol line” mean the + end or the − end? (a) − (negative) (b) + (positive)
14. 14.💡 6 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 4 is taken out of its holder. How many bulbs glow?
15. 15.✏️ In a circuit diagram, wires are usually drawn as … (a) wavy lines (b) little stars (c) straight lines (d) dotted circles
16. 16.Which job needs a servo motor? (a) turn to an exact angle (b) show a status light (c) spin a robot’s wheels (d) move water to plants
17. 17.⚡ What does a table fan mainly change electricity into? (a) sound (b) heat (c) light (d) movement
18. 18.True or false: a tilt switch closes when tipped over. (a) False (b) True
19. 19.Which of these gives us electricity? (a) an air conditioner (b) a water pump (c) a washing machine (d) a solar panel
20. 20.Which of these is not an IoT device? (a) a fitness band with app (b) a Wi-Fi weather station (c) an app-controlled bulb (d) a pencil sharpener
21. 21.🔋 A 3 V battery and one 1.5 V cell are joined in series, all facing the same way. What is the total voltage (in volts)? =
22. 22.⏱️ A program says “wait 8250 ms”. How many seconds is that? =
23. 23.🧮 Two resistors in parallel give a total that is … (a) their sum (b) more than either one (c) less than either one (d) always zero
24. 24.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
25. 25.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) False (b) True
26. 26.⚡ A 4.5 W device works on 9 V. What current does it take (in amperes)? =
27. 27.🔢 To run one loop of a plant-watering program, what comes right after “read the soil sensor”? (a) switch the pump on/off (b) wait a few seconds (c) compare with the limit
28. 28.🔋 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)? =
29. 29.🔘 Which kind of switch closes when tipped over? (a) a toggle switch (b) a reed switch (c) a tilt switch (d) a slide switch
30. 30.🔁 repeat 2 times { repeat 5 times { beep } }
    How many beeps are there?
31. 31.💡 3 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 3 is taken out of its holder. Does bulb 1 glow? (a) Yes (b) No
32. 32.True or false: to touch a switch when wet is safe. (a) True (b) False
33. 33.🔺 A current of 2.5 A flows when 15 V is joined across a resistor. What is its resistance (in ohms)?
34. 34.What does a fuse do? (a) glows using little power (b) blows if current is high (c) is a resistance knob (d) makes a beeping sound
35. 35.True or false: a wind-up toy has no microcontroller inside. (a) True (b) False
36. 36.True or false: triangle, bar and arrows is the symbol for a resistor. (a) True (b) False
37. 37.✏️ In a cell symbol, which line is the + terminal? (a) the shorter line (b) the longer line (c) neither line (d) both lines
38. 38.True or false: “one out, the rest glow” is true of a series circuit. (a) True (b) False
39. 39.🌈 A resistor has the colour bands red, brown, black. What is its value (in ohms)?
40. 40.Which of these is not safe? (a) use small battery cells (b) dry your hands first (c) stop if a part gets hot (d) touch a fallen wire

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