Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 364 · 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.Which of these is a conductor? (a) a rubber band (b) a metal paper clip (c) a woollen thread (d) a cotton thread
2. 2.📶 How many states can a digital pin have? (a) a thousand (b) one (c) ten (d) two
3. 3.🧩 Which component has coloured bands? (a) motor (b) buzzer (c) resistor (d) capacitor
4. 4.🔺 A current of 1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
5. 5.🌐 A soil sensor sends a reading to an app every 20 minutes. How many readings arrive in 6 hours?
6. 6.🔺 A current of 10 mA flows when 2.2 V is joined across a resistor. What is its resistance (in ohms)?
7. 7.True or false: a table fan mainly makes movement. (a) False (b) True
8. 8.⚡ Power tells us … (a) energy used each second (b) the size of a cell (c) the length of a wire (d) the colour of light
9. 9.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
10. 10.What does a slide switch do? (a) stays where you flip it (b) slides side to side (c) flips up or down (d) works only while pressed
11. 11.🔍 Which sensor would you use to warn of a gas leak? (a) a distance sensor (b) a gas sensor (c) a sound sensor (d) a temperature sensor
12. 12.🔺 A current of 50 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
13. 13.🔍 Which is the odd one out? (a) a table fan (b) an LED lamp (c) an electric drill (d) an exhaust fan
14. 14.📏 How many kilo-ohms (kΩ) is 7200 Ω? =
15. 15.🤖 Microcontroller or laptop: which one runs one small program? (a) microcontroller (b) laptop
16. 16.⚠️ Is it safe to open a phone charger? (a) safe (b) not safe
17. 17.Which job needs a gas sensor? (a) warn of a gas leak (b) switch on lamps at dusk (c) open blinds at sunrise (d) measure classroom noise
18. 18.💡 2 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 2 is taken out of its holder. Does bulb 1 glow? (a) No (b) Yes
19. 19.True or false: to make a parking alarm, use a light sensor. (a) False (b) True
20. 20.🧩 Which component beeps for an alarm? (a) thermistor (b) capacitor (c) potentiometer (d) buzzer
21. 21.What does a capacitor do? (a) lets current go one way (b) glows using little power (c) smooths a wobbly supply (d) limits the current
22. 22.Which of these mainly gives out heat? (a) a traffic signal (b) a buzzer (c) a water heater (d) a ceiling fan
23. 23.🔍 An object is 306 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
24. 24.🔘 Which kind of switch closes when tipped over? (a) a toggle switch (b) a tilt switch (c) a push button (d) a slide switch
25. 25.Which drawing is the symbol for a voltmeter? (a) a circle with V inside (b) many long-short pairs (c) a dot where wires meet (d) two equal parallel lines
26. 26.True or false: on an LED, the shorter leg is the anode (+). (a) False (b) True
27. 27.🔋 2 identical 3 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
28. 28.🔗 Series or parallel circuit: “one bulb out, all go out”? (a) parallel (b) series
29. 29.🔺 A current of 0.1 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
30. 30.⏱️ loop forever { LED ON; wait 850 ms; LED OFF; wait 150 ms }
    How many times does the LED blink in 7 seconds?
31. 31.Which job needs an LED? (a) beep an alarm (b) spin a robot’s wheels (c) move water to plants (d) show a status light
32. 32.🔁 What does a variable do in a program? (a) stores a value (b) measures light (c) joins two wires (d) blinks an LED
33. 33.🔍 Which sensor would you use to water a dry plant? (a) a rain sensor (b) a gas sensor (c) a motion sensor (d) a soil moisture sensor
34. 34.🌐 Is a smart energy meter an IoT device? (a) not an IoT device (b) an IoT device
35. 35.🗺️ In an input → process → output plan, is “decide if soil is dry” the input, the process or the output? (a) output (b) process (c) input
36. 36.🔢 To plan an electronics project, which is the FIRST step? (a) pick a problem to solve (b) test it and fix it (c) build it with an adult (d) list inputs and outputs
37. 37.🧮 A 2.8 V battery is joined to 2 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
38. 38.Which of these is a good habit? (a) share the Wi-Fi key (b) post your live location (c) ignore update messages (d) install software updates
39. 39.🔍 A distance sensor sends a sound pulse and hears the echo 20 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
40. 40.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed

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