Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 675 · 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.🔋 How many 1.2 V cells must be joined in series to give 3.6 V?
2. 2.🏠 Which is a smart-home example? (a) a printed map (b) lights on from an app (c) a candle in a jar (d) a hand fan
3. 3.🔐 Privacy for a smart device means controlling … (a) how loud it beeps (b) its battery size (c) who can see your data (d) its colour
4. 4.⏱️ A program says “wait 500 ms”. How many seconds is that? =
5. 5.🔍 Which is the odd one out? (a) a rubber band (b) a steel spoon (c) a wooden stick (d) a dry cork
6. 6.Which of these is an insulator? (a) a woollen thread (b) a steel spoon (c) an iron nail (d) a copper wire
7. 7.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 2.5 V supply. What current flows (in mA)?
8. 8.🧮 Two resistors in parallel give a total that is … (a) their sum (b) less than either one (c) more than either one (d) always zero
9. 9.✏️ In a circuit diagram, wires are usually drawn as … (a) little stars (b) dotted circles (c) wavy lines (d) straight lines
10. 10.⚠️ Is it safe to stop if a part gets hot? (a) not safe (b) safe
11. 11.🧮 Resistors of 150 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
12. 12.Which job needs a distance sensor? (a) open blinds at sunrise (b) close a window in rain (c) start a fan when hot (d) stop a robot near walls
13. 13.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
14. 14.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
15. 15.⚡ A cell changes stored chemical energy into which kind of energy? (a) wind energy (b) electrical energy (c) sound energy (d) nuclear energy
16. 16.🔗 Series or parallel circuit: “one bulb out, all go out”? (a) parallel (b) series
17. 17.True or false: “each gets the full volts” is true of a series circuit. (a) True (b) False
18. 18.True or false: “a break stops every bulb” is true of a series circuit. (a) True (b) False
19. 19.🧮 Four equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
20. 20.🧮 A 3 V battery is joined to 3 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
21. 21.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
22. 22.🔋 8 identical 3 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
23. 23.What does a reed switch do? (a) works only while pressed (b) springs back when let go (c) closes near a magnet (d) slides side to side
24. 24.🔁 count = 3
    repeat 2 times { count = count + 4 }
    What is count at the end?
25. 25.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
26. 26.🔘 A cell and a bulb are joined to 3 side-by-side paths with one switch on each path — A, B and C (parallel). A is ON, B is OFF and C is ON. Does the bulb glow? (a) No (b) Yes
27. 27.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V × I (c) P = V ÷ I (d) P = V + I
28. 28.🔍 Which sensor would you use to start a fan when hot? (a) a rain sensor (b) a temperature sensor (c) a gas sensor (d) a distance sensor
29. 29.🔋 On a cell, does “the flat end” mean the + end or the − end? (a) + (positive) (b) − (negative)
30. 30.🤖 if (light < 300) { lamp ON } else { lamp OFF }
    The light sensor reads 203. What happens? (a) lamp OFF (b) lamp ON
31. 31.⚠️ Is it safe to use mains for a project? (a) not safe (b) safe
32. 32.True or false: a laptop needs much more power. (a) False (b) True
33. 33.🔺 A current of 40 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
34. 34.🧭 Which part of a microcontroller board runs the program? (a) the main chip (b) the pins (c) the reset button (d) the USB port
35. 35.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
36. 36.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 2.75 V supply. What current flows (in mA)?
37. 37.⚡ A 9 W device works on 9 V. What current does it take (in amperes)? =
38. 38.🔍 Which is the odd one out? (a) use a cable with cuts (b) climb an electric pole (c) fly a kite near wires (d) keep drinks far away
39. 39.True or false: to touch a switch when wet is not safe. (a) False (b) True
40. 40.🔺 A current of 20 mA flows when 4.4 V is joined across a resistor. What is its resistance (in ohms)?

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