Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 442 · 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.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
2. 2.🔺 A current of 40 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
3. 3.🤖 if (temperature > 36) { show “Hot” } else if (temperature > 19) { show “Warm” } else { show “Cool” }
   The temperature is 41 °C. What is shown? (a) Warm (b) Hot (c) Cool
4. 4.🔁 total = 0
   for i = 1 to 8 { total = total + i }
   What is total at the end?
5. 5.True or false: to accept every permission is a risky habit. (a) False (b) True
6. 6.🤖 When the main loop of a microcontroller program ends, what happens? (a) it deletes itself (b) it stops forever (c) it starts again (d) the board breaks
7. 7.🧩 Which component makes a beeping sound? (a) diode (b) resistor (c) potentiometer (d) buzzer
8. 8.🧮 A 3 V battery is joined to 3 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
9. 9.🔘 A cell, a bulb and switches A and B are joined one after another in a single loop (series). A is ON and B is OFF. Does the bulb glow? (a) No (b) Yes
10. 10.Which drawing is the symbol for a cell? (a) two equal parallel lines (b) triangle, bar and arrows (c) a circle with A inside (d) a long and a short line
11. 11.What does a transistor do? (a) turns a fan or wheels (b) boosts a small signal (c) blows if current is high (d) is a resistance knob
12. 12.🧮 Resistors of 22 Ω, 10 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
13. 13.What does the phone app do? (a) stores data online (b) measures the real world (c) acts on a command (d) shows data to you
14. 14.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a closed circuit (c) an open circuit (d) a full circuit
15. 15.🔘 Which kind of switch flips up or down? (a) a toggle switch (b) a tilt switch (c) a push button (d) a slide switch
16. 16.✏️ In a circuit diagram, wires are usually drawn as … (a) dotted circles (b) little stars (c) wavy lines (d) straight lines
17. 17.🔘 A cell and a bulb are joined to 2 side-by-side paths with one switch on each path — A and B (parallel). A is ON and B is OFF. Does the bulb glow? (a) No (b) Yes
18. 18.🤖 Microcontroller or laptop: which one needs much more power? (a) laptop (b) microcontroller
19. 19.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
20. 20.Which of these is a good habit? (a) turn off unused gadgets (b) ignore update messages (c) tap unknown app links (d) keep factory passwords
21. 21.Which drawing is the symbol for a diode? (a) a circle with A inside (b) triangle against a bar (c) a straight line (d) many long-short pairs
22. 22.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
23. 23.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a dry cork across the gap. Does the bulb glow? (a) No (b) Yes
24. 24.⚠️ Is it safe to climb an electric pole? (a) safe (b) not safe
25. 25.Which of these is a good habit? (a) share the Wi-Fi key (b) tap unknown app links (c) log out of shared phones (d) reuse one password
26. 26.⚠️ What protects home wiring by melting or tripping when too much current flows? (a) a plug top (b) a bulb (c) a fuse or MCB (d) a long wire
27. 27.🧩 Which component limits the current? (a) potentiometer (b) fuse (c) resistor (d) LDR
28. 28.🔍 Which is the odd one out? (a) a glass marble (b) a paper strip (c) a wooden stick (d) a steel coin
29. 29.🔗 Series or parallel circuit: “used in house wiring”? (a) series (b) parallel
30. 30.✏️ In a circuit diagram, which part is drawn as a plain rectangle? (a) motor (b) wire (c) resistor (d) ammeter
31. 31.🔌 Is a sound sensor an input or an output for a microcontroller? (a) output (b) input
32. 32.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
33. 33.🧮 A 220 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
34. 34.🔋 On a cell, does “the flat end” mean the + end or the − end? (a) − (negative) (b) + (positive)
35. 35.🔋 3 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
36. 36.🔺 A current of 50 mA flows when 23.5 V is joined across a resistor. What is its resistance (in ohms)?
37. 37.🤖 if (moisture < 40) { pump ON } else { pump OFF }
    The soil moisture sensor reads 31 %. What happens? (a) pump OFF (b) pump ON
38. 38.True or false: a digital alarm clock has no microcontroller inside. (a) True (b) False
39. 39.🔘 A bulb and a cell are joined through 2 switches on 2 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?
40. 40.🔍 Which is the odd one out? (a) a woollen thread (b) a safety pin (c) a paper strip (d) a cotton thread

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