Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 776 · 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 red LED (it uses 2 V) is joined with a 200 Ω resistor to a 6 V supply. What current flows (in mA)?
2. 2.🌐 Is a plain table fan an IoT device? (a) an IoT device (b) not an IoT device
3. 3.🔁 x = 2
   repeat 1 time { x = x × 2 }
   What is x at the end?
4. 4.Which of these is an output? (a) a buzzer (b) a keypad (c) a light sensor (d) a temperature sensor
5. 5.What does a resistor do? (a) is a resistance knob (b) has coloured bands (c) lets current go one way (d) makes a beeping sound
6. 6.🤖 Microcontroller or laptop: which one has no screen of its own? (a) microcontroller (b) laptop
7. 7.🔺 A current of 40 mA flows when 16 V is joined across a resistor. What is its resistance (in ohms)?
8. 8.🔗 Series or parallel circuit: “a single current path”? (a) parallel (b) series
9. 9.Which of these is a risky habit? (a) share only needed data (b) read app permissions (c) turn off unused gadgets (d) post your live location
10. 10.🔢 To plan an electronics project, which comes first: “list inputs and outputs” or “build it with an adult”? (a) build it with an adult (b) list inputs and outputs
11. 11.🔍 An object is 85 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
12. 12.💡 A battery lights 3 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) the same (b) dimmer (c) brighter
13. 13.💡 3 identical bulbs are in parallel and each one takes 0.25 A. What total current (in amperes) comes from the battery? =
14. 14.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is ON (c) a cell is taken out (d) a wire has come loose
15. 15.🔁 What does “count = count + 1” do? (a) sets count to 1 (b) prints 1 (c) adds 1 to count (d) takes 1 away
16. 16.🤖 Does a spinning top usually have a microcontroller inside? (a) Yes (b) No
17. 17.True or false: a small empty box is the symbol for a resistor. (a) True (b) False
18. 18.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
19. 19.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) less than either one (c) their sum (d) always zero
20. 20.True or false: “each gets the full volts” is true of a series circuit. (a) False (b) True
21. 21.🗺️ Before building a project, what should you write down first? (a) the box colour (b) nothing at all (c) inputs and outputs (d) the final price
22. 22.💡 6 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 3 is taken out of its holder. Does bulb 5 glow? (a) Yes (b) No
23. 23.🔁 count = 1
    while (count < 13) { count = count + 4 }
    How many times does the loop run?
24. 24.🔋 A 12 V battery and four 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
25. 25.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
26. 26.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in parallel (b) not joined (c) in series (d) by Wi-Fi
27. 27.🔁 count = 5
    repeat 8 times { count = count + 4 }
    What is count at the end?
28. 28.💡 2 identical bulbs are joined in series with a 4 V battery (ideal wires). How many volts does each bulb get? =
29. 29.⏱️ loop forever { LED ON; wait 650 ms; LED OFF; wait 750 ms }
    How many milliseconds does one blink (ON + OFF) take?
30. 30.Which of these is a good habit? (a) ignore update messages (b) post your live location (c) accept every permission (d) set a strong password
31. 31.✏️ In a circuit diagram, which part is drawn as a small empty box? (a) motor (b) wire (c) resistor (d) bulb
32. 32.⏱️ A program says “wait 2000 ms”. How many seconds is that? =
33. 33.True or false: a small empty box is the symbol for a switch. (a) False (b) True
34. 34.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. Does the bulb glow? (a) No (b) Yes
35. 35.⚡ Which tiny particles drift along a metal wire to carry the current? (a) water drops (b) electrons (c) photons (d) dust particles
36. 36.True or false: to use daylight to read saves electricity. (a) True (b) False
37. 37.🌈 In the resistor colour code, which number does white stand for?
38. 38.🤖 if (distance < 10) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 2 cm. What happens? (a) buzzer beeps (b) buzzer is silent
39. 39.Which of these is a good habit? (a) keep factory passwords (b) accept every permission (c) share the Wi-Fi key (d) set up with a parent
40. 40.True or false: “one bulb out, all go out” is true of a parallel circuit. (a) True (b) False

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