Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 956 · 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 through a 400 Ω resistor. What is the voltage across it (in volts)? =
2. 2.🔍 For a microcontroller, is a sensor an input or an output? (a) a power source (b) an input (c) a fuse (d) an output
3. 3.🔍 Which is the odd one out? (a) a Wi-Fi smart plug (b) a Wi-Fi weather station (c) a battery torch (d) a Wi-Fi doorbell camera
4. 4.🧩 Which component beeps for an alarm? (a) resistor (b) transistor (c) diode (d) buzzer
5. 5.🔍 A distance sensor sends a sound pulse and hears the echo 13 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
6. 6.🔁 repeat 6 times { repeat 4 times { beep } }
   How many beeps are there?
7. 7.Which of these is a good habit? (a) cover unused cameras (b) keep factory passwords (c) reuse one password (d) accept every permission
8. 8.Which job is done by the main chip? (a) connect sensors and LEDs (b) restarts the program (c) runs the program (d) brings power and code
9. 9.True or false: an electric iron mainly gives out heat. (a) False (b) True
10. 10.🌈 A resistor has the colour bands green, white, orange. What is its value in kilo-ohms (kΩ)? =
11. 11.🧩 Which component senses how hot it is? (a) LED (b) motor (c) thermistor (d) resistor
12. 12.🔺 A current of 2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
13. 13.🔗 Series or parallel circuit: “bulbs share the voltage”? (a) parallel (b) series
14. 14.🔢 To plan an electronics project, what comes right after “draw the circuit diagram”? (a) pick a problem to solve (b) test it and fix it (c) list inputs and outputs (d) build it with an adult
15. 15.🔁 count = 1
    repeat 8 times { count = count + 5 }
    What is count at the end?
16. 16.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
17. 17.✏️ In a circuit diagram, which part is drawn as a circle with V inside? (a) motor (b) battery (c) voltmeter (d) bulb
18. 18.Which of these is safe? (a) throw cells in a fire (b) use small battery cells (c) use mains for a project (d) open a phone charger
19. 19.Which of these is a risky habit? (a) log out of shared phones (b) accept every permission (c) share only needed data (d) read app permissions
20. 20.Which of these is an output? (a) a sound sensor (b) a turning knob (c) a motor (d) a keypad
21. 21.🔌 Why are electric wires covered in plastic? (a) plastic is an insulator (b) plastic makes current (c) to make them heavy (d) plastic is a conductor
22. 22.Which drawing is the symbol for a voltmeter? (a) triangle, bar and arrows (b) triangle against a bar (c) a small empty box (d) a circle with V inside
23. 23.🔋 Cells joined + to − in a row (series) give … (a) a bigger voltage (b) no voltage (c) the same voltage (d) a smaller voltage
24. 24.🔺 A current of 50 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
25. 25.🔢 To run one loop of a plant-watering program, which comes first: “wait a few seconds” or “compare with the limit”? (a) compare with the limit (b) wait a few seconds
26. 26.Which of these is an input? (a) a keypad (b) a small display (c) a motor (d) a servo motor
27. 27.🔍 Which is the odd one out? (a) a siren (b) an LED lamp (c) a traffic signal (d) a street light
28. 28.True or false: an electric kettle mainly gives out heat. (a) False (b) True
29. 29.🔘 A cell, a bulb and switches A, B and C are joined one after another in a single loop (series). A is OFF, B is ON and C is ON. Does the bulb glow? (a) Yes (b) No
30. 30.💡 Why is house wiring done in parallel? (a) each gets full voltage (b) to make bulbs dim (c) to save copper only (d) so all go off together
31. 31.What does a tilt switch do? (a) closes near a magnet (b) slides side to side (c) closes when tipped over (d) stays where you flip it
32. 32.What does a reed switch do? (a) closes near a magnet (b) stays where you flip it (c) closes when tipped over (d) springs back when let go
33. 33.🔁 count = 9
    repeat 3 times { count = count + 4 }
    What is count at the end?
34. 34.🧮 Resistors of 470 Ω, 10 Ω, 150 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
35. 35.Which of these is the process? (a) a motion sensor signal (b) an alert on the phone (c) a buzzer beeps (d) check if temp > 30
36. 36.Which of these is the output? (a) a temperature reading (b) a light level reading (c) an LED lights up (d) decide if soil is dry
37. 37.🔺 A 24 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
38. 38.What does a buzzer do? (a) makes a beeping sound (b) has coloured bands (c) boosts a small signal (d) blows if current is high
39. 39.⏱️ repeat 2 times { buzzer ON; wait 300 ms; buzzer OFF; wait 800 ms }
    How many milliseconds does this take in all?
40. 40.🔁 count = 7
    repeat 3 times { count = count + 7 }
    What is count at the end?

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