Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 798 · 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 current of 50 mA flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
2. 2.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
   set pin 7 LOW
   set pin 8 HIGH
   set pin 7 LOW
   set pin 8 LOW
   Is the LED ON or OFF at the end? (a) OFF (b) ON
3. 3.🔁 repeat 5 times { repeat 5 times { beep } }
   How many beeps are there?
4. 4.⏱️ loop forever { LED ON; wait 1000 ms; LED OFF; wait 800 ms }
   How many milliseconds does one blink (ON + OFF) take?
5. 5.⚡ What does an exhaust fan mainly change electricity into? (a) sound (b) movement (c) heat (d) light
6. 6.🤖 if (temperature > 36) { show “Hot” } else if (temperature > 23) { show “Warm” } else { show “Cool” }
   The temperature is 40 °C. What is shown? (a) Cool (b) Warm (c) Hot
7. 7.🔍 Which is the odd one out? (a) touch a switch when wet (b) touch a fallen wire (c) use mains for a project (d) dry your hands first
8. 8.🔌 Is a servo motor an input or an output for a microcontroller? (a) output (b) input
9. 9.⚡ What does a water heater mainly change electricity into? (a) movement (b) heat (c) light (d) sound
10. 10.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
11. 11.🔋 What is a battery? (a) one single wire (b) two or more cells joined (c) a kind of bulb (d) a switch with a lid
12. 12.Which of these is safe? (a) poke things in a socket (b) dry your hands first (c) climb an electric pole (d) use a cable with cuts
13. 13.💡 3 identical bulbs are in parallel and each bulb has its own switch on its path. 2 of the switches are OFF and the rest are ON. How many bulbs glow?
14. 14.True or false: “own switch for each bulb” is true of a series circuit. (a) True (b) False
15. 15.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) − (negative) (b) + (positive)
16. 16.Which of these is a good habit? (a) accept every permission (b) share camera links (c) tap unknown app links (d) read app permissions
17. 17.⏱️ loop forever { LED ON; wait 550 ms; LED OFF; wait 400 ms }
    How many milliseconds does one blink (ON + OFF) take?
18. 18.Which drawing is the symbol for a switch? (a) triangle, bar and arrows (b) two or more cell symbols (c) a line lifted at a gap (d) one tall, one short bar
19. 19.🌐 In an IoT system, which part carries the data? (a) microcontroller (b) phone app (c) Wi-Fi (d) actuator
20. 20.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I + R (c) V = I ÷ R (d) V = I × R
21. 21.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V + I (c) P = I ÷ V (d) P = V × I
22. 22.Which of these mainly makes movement? (a) a toaster (b) an electric toy car (c) a room heater (d) a doorbell
23. 23.🔍 Which is the odd one out? (a) an LED (b) a temperature sensor (c) a servo motor (d) a water pump
24. 24.Which of these uses electricity? (a) a power station (b) a computer (c) a wind turbine (d) a solar panel
25. 25.🔋 A 3 V battery and two 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
26. 26.🔺 A current of 50 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
27. 27.🔍 Which is the odd one out? (a) a keypad (b) a small display (c) a servo motor (d) a buzzer
28. 28.🧮 Two resistors in parallel give a total that is … (a) their sum (b) always zero (c) less than either one (d) more than either one
29. 29.🔋 On a cell, does “the shorter symbol line” mean the + end or the − end? (a) − (negative) (b) + (positive)
30. 30.✏️ In a cell symbol, which line is the + terminal? (a) both lines (b) the shorter line (c) neither line (d) the longer line
31. 31.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to limit the current (c) to make it brighter (d) to store charge
32. 32.🔐 Privacy for a smart device means controlling … (a) its battery size (b) who can see your data (c) how loud it beeps (d) its colour
33. 33.🔢 To run one loop of a plant-watering program, what comes right after “read the soil sensor”? (a) wait a few seconds (b) switch the pump on/off (c) compare with the limit
34. 34.💡 5 identical bulbs are joined in series with a 5 V battery (ideal wires). How many volts does each bulb get? =
35. 35.True or false: to poke things in a socket is not safe. (a) False (b) True
36. 36.✏️ In a circuit diagram, which part is drawn as a circle with A inside? (a) ammeter (b) battery (c) resistor (d) capacitor
37. 37.🔺 A current of 40 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
38. 38.🔁 What does “count = count + 1” do? (a) adds 1 to count (b) sets count to 1 (c) prints 1 (d) takes 1 away
39. 39.True or false: a room heater mainly gives out heat. (a) False (b) True
40. 40.Which of these means the circuit is open? (a) all wires are joined (b) a wire is cut (c) the loop is complete (d) the switch is ON

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