Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 275 · 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.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 900 ms }
   How many times does the LED blink in 9 seconds?
2. 2.🔦 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 safety pin. Does the bulb glow? (a) No (b) Yes
3. 3.🧩 Which component is a resistance knob? (a) thermistor (b) potentiometer (c) buzzer (d) fuse
4. 4.🔗 Series or parallel circuit: “own switch for each bulb”? (a) series (b) parallel
5. 5.🌈 A resistor has the colour bands orange, yellow, red. What is its value (in ohms)?
6. 6.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a capacitor (c) a diode (d) a resistor
7. 7.🔁 count = 5
   repeat 7 times { count = count + 3 }
   What is count at the end?
8. 8.⚙️ Which actuator would you use to turn to an exact angle? (a) a display (b) a servo motor (c) a pump (d) a motor
9. 9.🔺 A current of 50 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
10. 10.Which job needs a soil moisture sensor? (a) switch on lamps at dusk (b) measure classroom noise (c) warn of a gas leak (d) water a dry plant
11. 11.True or false: a tilt switch closes when tipped over. (a) False (b) True
12. 12.Which of these is not safe? (a) take cells out after use (b) keep drinks far away (c) fly a kite near wires (d) build with an adult near
13. 13.Which of these is the output? (a) an LED lights up (b) a soil moisture reading (c) check if temp > 30 (d) a temperature reading
14. 14.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 kilowatt-hour (kWh) (c) 1 ampere (d) 1 watt
15. 15.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
16. 16.⏱️ How many milliseconds is a wait of 4.4 seconds?
17. 17.Which of these is the process? (a) an LED lights up (b) a buzzer beeps (c) a motion sensor signal (d) compare with a limit
18. 18.True or false: “a soil moisture reading” is the process. (a) False (b) True
19. 19.Which of these is an input? (a) a light sensor (b) a motor (c) a buzzer (d) a water pump
20. 20.🤖 Which is a safe power source for a beginner microcontroller board? (a) a wall socket directly (b) bare mains wires (c) USB or a 9 V battery (d) a 230 V cable
21. 21.⏱️ How many milliseconds is a wait of 0.1 seconds?
22. 22.What does a capacitor do? (a) stores a little charge (b) lets current go one way (c) beeps for an alarm (d) limits the current
23. 23.Which job is done by the pins? (a) shows the board is on (b) restarts the program (c) brings power and code (d) connect sensors and LEDs
24. 24.🔐 Is it a good or a risky habit to read app permissions? (a) risky habit (b) good habit
25. 25.🔋 How many 2 V cells must be joined in series to give 12 V?
26. 26.Which drawing is the symbol for a junction? (a) a dot where wires meet (b) triangle against a bar (c) a circle with an X in it (d) a circle with a cross
27. 27.True or false: to change default passwords is a risky habit. (a) True (b) False
28. 28.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I + R (c) V = R ÷ I (d) V = I × R
29. 29.📏 In the water-pipe picture of a circuit, resistance is like … (a) the flow of water (b) a bigger tank (c) the water pressure (d) a narrow pipe
30. 30.🌈 A resistor has the colour bands green, blue, red. What is its value in kilo-ohms (kΩ)? =
31. 31.🗺️ Before building a project, what should you write down first? (a) the final price (b) nothing at all (c) the box colour (d) inputs and outputs
32. 32.📏 How many kilo-ohms (kΩ) is 800 Ω? =
33. 33.🧭 Which part of a microcontroller board shows the board is on? (a) the power LED (b) the voltage regulator (c) the reset button (d) the USB port
34. 34.Which of these mainly gives out light? (a) a siren (b) an exhaust fan (c) an electric toy car (d) an LED lamp
35. 35.Which job is done by the voltage regulator? (a) connect sensors and LEDs (b) restarts the program (c) runs the program (d) keeps the voltage steady
36. 36.💡 What does LED stand for? (a) large electric dial (b) light-emitting diode (c) light energy dial (d) low energy device
37. 37.Which of these is measured in amperes (A)? (a) resistance (b) voltage (c) power (d) current
38. 38.Which of these usually has a microcontroller inside? (a) a candle (b) a wind-up toy (c) a digital thermometer (d) a bicycle bell
39. 39.Which of these means the circuit is closed? (a) a wire is cut (b) a wire has come loose (c) the switch is OFF (d) all wires are joined
40. 40.True or false: to open blinds at sunrise, use a temperature sensor. (a) False (b) True

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