Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 782 · 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 25 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
2. 2.💡 What does LED stand for? (a) light-emitting diode (b) large electric dial (c) low energy device (d) light energy dial
3. 3.✏️ In a circuit diagram, which part is drawn as a circle with an X in it? (a) resistor (b) ammeter (c) bulb (d) capacitor
4. 4.🔺 A current of 20 mA flows when 6.6 V is joined across a resistor. What is its resistance (in ohms)?
5. 5.🔘 Which kind of switch slides side to side? (a) a push button (b) a reed switch (c) a toggle switch (d) a slide switch
6. 6.🗺️ In an input → process → output plan, is “count button presses” the input, the process or the output? (a) process (b) output (c) input
7. 7.⚙️ Which actuator would you use to show a status light? (a) a display (b) an LED (c) a pump (d) a motor
8. 8.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
9. 9.True or false: to use mains for a project is not safe. (a) False (b) True
10. 10.🔍 Which is the odd one out? (a) install software updates (b) log out of shared phones (c) share camera links (d) share only needed data
11. 11.Which of these is measured in amperes (A)? (a) current (b) how much a part resists (c) energy used each second (d) resistance
12. 12.True or false: “decide if soil is dry” is the input. (a) True (b) False
13. 13.Which drawing is the symbol for a battery? (a) a line lifted at a gap (b) a circle with M inside (c) two or more cell symbols (d) a long and a short line
14. 14.Which drawing is the symbol for a capacitor? (a) a line lifted at a gap (b) two equal parallel lines (c) a circle with A inside (d) many long-short pairs
15. 15.Which of these is an output? (a) a temperature sensor (b) a sound sensor (c) a keypad (d) a buzzer
16. 16.🔁 repeat 4 times { repeat 2 times { beep } }
    How many beeps are there?
17. 17.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V × R (c) I = V ÷ R (d) I = V + R
18. 18.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 HIGH
    set pin 8 LOW
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) OFF (b) ON
19. 19.💡 3 identical bulbs are in parallel and each one takes 0.25 A. What total current (in amperes) comes from the battery? =
20. 20.🔢 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
21. 21.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a steel coin across the gap. Does the bulb glow? (a) No (b) Yes
22. 22.🔍 Which is the odd one out? (a) poke things in a socket (b) fly a kite near wires (c) fly kites in open fields (d) touch a switch when wet
23. 23.True or false: on an LED, the shorter leg is the anode (+). (a) True (b) False
24. 24.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
25. 25.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
26. 26.True or false: “many paths for current” is true of a series circuit. (a) True (b) False
27. 27.🤖 if (temperature > 25) { fan ON } else { fan OFF }
    The temperature sensor reads 19 °C. What happens? (a) fan ON (b) fan OFF
28. 28.🤖 Which is a safe power source for a beginner microcontroller board? (a) a wall socket directly (b) a 230 V cable (c) bare mains wires (d) USB or a 9 V battery
29. 29.🔋 Cells joined + to − in a row (series) give … (a) a smaller voltage (b) no voltage (c) the same voltage (d) a bigger voltage
30. 30.🔌 Which part of a screwdriver should an electrician hold? (a) the steel shaft (b) the bare end (c) the plastic handle (d) the metal tip
31. 31.What does the phone app do? (a) acts on a command (b) stores data online (c) shows data to you (d) reads values, decides
32. 32.🤖 if (temperature > 33) { show “Hot” } else if (temperature > 20) { show “Warm” } else { show “Cool” }
    The temperature is 25 °C. What is shown? (a) Hot (b) Cool (c) Warm
33. 33.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V + I (c) P = I ÷ V (d) P = V × I
34. 34.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) not joined (b) in parallel (c) in series (d) by Wi-Fi
35. 35.🔺 A 9 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
36. 36.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
37. 37.📶 Digital or analog: a tilt switch: on or off? (a) analog (b) digital
38. 38.🔍 A distance sensor sends a sound pulse and hears the echo 3 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
39. 39.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
40. 40.🔍 Which is the odd one out? (a) dry your hands first (b) build with an adult near (c) poke things in a socket (d) stay away from pylons

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