Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 860 · 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.⚡ What does an electric kettle mainly change electricity into? (a) heat (b) movement (c) sound (d) light
2. 2.💡 An LED is joined to a 3 V battery through a 330 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) may burn out (b) lights up (c) does not light
3. 3.What does a toggle switch do? (a) stays where you flip it (b) works only while pressed (c) slides side to side (d) closes when tipped over
4. 4.🔋 On a cell, does “usually the black wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
5. 5.True or false: on a cell, “usually the red wire” means the − (negative) end. (a) False (b) True
6. 6.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = R ÷ V (c) I = V + R (d) I = V × R
7. 7.⚡ What does a torch mainly change electricity into? (a) heat (b) sound (c) movement (d) light
8. 8.✏️ In a circuit diagram, which part is drawn as a circle with V inside? (a) bulb (b) junction (c) cell (d) voltmeter
9. 9.🔋 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)? =
10. 10.💡 3 identical bulbs are joined in series with a 4.5 V battery (ideal wires). How many volts does each bulb get? =
11. 11.🔺 A current of 2 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
12. 12.Which of these is a conductor? (a) a rubber band (b) a cotton thread (c) an iron nail (d) a plastic ruler
13. 13.💡 A battery lights 2 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) brighter (b) the same (c) dimmer
14. 14.🔐 A smart-camera app asks for your school name and home address. What should you do? (a) share it with friends (b) post it online (c) type it all in (d) ask a parent first
15. 15.🔗 Series or parallel circuit: “a single current path”? (a) parallel (b) series
16. 16.🔘 A bulb and a cell are joined through 4 switches on 4 side-by-side paths, one switch on each path (parallel). What is the smallest number of switches that must be ON to light the bulb?
17. 17.Which of these is the input? (a) the fan starts (b) the pump turns on (c) decide if soil is dry (d) a temperature reading
18. 18.🤖 if (sound > 80) { red LED ON } else { green LED ON }
    The sound sensor reads 89. What happens? (a) green LED ON (b) red LED ON
19. 19.⚡ Which formula gives electric power? (a) P = V + I (b) P = I ÷ V (c) P = V × I (d) P = V ÷ I
20. 20.Which of these is true of a series circuit? (a) a single current path (b) one out, the rest glow (c) own switch for each bulb (d) many paths for current
21. 21.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
22. 22.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
23. 23.🔘 Which kind of switch works only while pressed? (a) a slide switch (b) a reed switch (c) a tilt switch (d) a push button
24. 24.⏱️ How many milliseconds is a wait of 0.5 seconds?
25. 25.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
26. 26.🧭 Which part of a microcontroller board connect sensors and LEDs? (a) the voltage regulator (b) the power LED (c) the pins (d) the USB port
27. 27.True or false: on an LED, the round-side leg is the anode (+). (a) False (b) True
28. 28.🔁 What must there be for a current to flow? (a) one loose end (b) a complete loop (c) a broken path (d) a plastic gap
29. 29.🔋 What is a battery? (a) one single wire (b) a kind of bulb (c) a switch with a lid (d) two or more cells joined
30. 30.Which job needs a servo motor? (a) beep an alarm (b) spin a robot’s wheels (c) show the temperature (d) turn to an exact angle
31. 31.⏱️ loop forever { LED ON; wait 800 ms; LED OFF; wait 950 ms }
    How many milliseconds does one blink (ON + OFF) take?
32. 32.Which job needs a motion sensor? (a) keep an incubator warm (b) close a window in rain (c) spot someone walking in (d) water a dry plant
33. 33.🔘 Which kind of switch closes when tipped over? (a) a toggle switch (b) a slide switch (c) a reed switch (d) a tilt switch
34. 34.🔍 Which is the odd one out? (a) decide if soil is dry (b) an LED lights up (c) the pump turns on (d) a buzzer beeps
35. 35.Which of these is an insulator? (a) a steel spoon (b) a graphite rod (c) a wooden stick (d) aluminium foil
36. 36.🧩 Which component is a resistance knob? (a) resistor (b) potentiometer (c) LDR (d) capacitor
37. 37.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
38. 38.True or false: on a cell, “the longer symbol line” means the + (positive) end. (a) True (b) False
39. 39.Which job is done by the USB port? (a) brings power and code (b) keeps the voltage steady (c) shows the board is on (d) connect sensors and LEDs
40. 40.True or false: on a cell, “usually the black wire” means the − (negative) end. (a) False (b) True

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