Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 341 · 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 drawing is the symbol for a cell? (a) a dot where wires meet (b) a plain rectangle (c) triangle, bar and arrows (d) a long and a short line
2. 2.🔐 A smart speaker is always listening for its wake word. What is a sensible habit? (a) tell it your passwords (b) mute it when not in use (c) put it in the bathroom (d) let strangers use it
3. 3.🔍 Which sensor would you use to spot someone walking in? (a) a motion sensor (b) a light sensor (c) a temperature sensor (d) a sound sensor
4. 4.What does a potentiometer do? (a) makes a beeping sound (b) boosts a small signal (c) is a resistance knob (d) blows if current is high
5. 5.🧮 A 50 Ω resistor is joined in series with two equal 20 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
6. 6.🧮 Two resistors in parallel give a total that is … (a) always zero (b) less than either one (c) their sum (d) more than either one
7. 7.🔘 A cell and a bulb are joined to two side-by-side paths: path 1 has switches A and B one after another, path 2 has switch C. A is OFF, B is OFF and C is OFF. Does the bulb glow? (a) Yes (b) No
8. 8.💡 An LED is joined to a 6 V battery through a 220 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) does not light (b) may burn out (c) lights up
9. 9.🔍 Which is the odd one out? (a) close the fridge quickly (b) leave the TV on standby (c) unplug idle chargers (d) use LED lamps
10. 10.🔢 To run one loop of a plant-watering program, which comes first: “read the soil sensor” or “compare with the limit”? (a) compare with the limit (b) read the soil sensor
11. 11.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 390 Ω resistor? (a) white-orange-brown (b) orange-white-black (c) orange-white-brown (d) orange-white-red
12. 12.⚡ A 0.375 W device works on 1.5 V. What current does it take (in amperes)? =
13. 13.Which of these is an output? (a) a temperature sensor (b) a motor (c) a motion sensor (d) a push button
14. 14.🌈 A resistor has the colour bands grey, violet, brown. What is its value (in ohms)?
15. 15.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
16. 16.🤖 if (sound > 70) { red LED ON } else { green LED ON }
    The sound sensor reads 56. What happens? (a) green LED ON (b) red LED ON
17. 17.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
18. 18.What does the actuator do? (a) shows data to you (b) measures the real world (c) reads values, decides (d) acts on a command
19. 19.What does the phone app do? (a) reads values, decides (b) carries the data (c) shows data to you (d) measures the real world
20. 20.True or false: “HIGH or LOW only” is a digital signal. (a) False (b) True
21. 21.🔺 A current of 10 mA flows when 3.3 V is joined across a resistor. What is its resistance (in ohms)?
22. 22.⏱️ loop forever { LED ON; wait 800 ms; LED OFF; wait 250 ms }
    How many milliseconds does one blink (ON + OFF) take?
23. 23.🔍 Which is the odd one out? (a) dry your hands first (b) build with an adult near (c) open a phone charger (d) take cells out after use
24. 24.📏 Which unit measures power? (a) watt (W) (b) ohm (Ω) (c) volt (V) (d) ampere (A)
25. 25.⏱️ loop forever { LED ON; wait 50 ms; LED OFF; wait 500 ms }
    How many milliseconds does one blink (ON + OFF) take?
26. 26.🧮 A 22 Ω resistor is joined in series with two equal 200 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
27. 27.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 volt (c) 1 kilowatt-hour (kWh) (d) 1 ampere
28. 28.🔁 count = 7
    repeat 9 times { count = count + 4 }
    What is count at the end?
29. 29.True or false: a toggle switch springs back when let go. (a) True (b) False
30. 30.🔍 Which sensor would you use to open blinds at sunrise? (a) a light sensor (b) a temperature sensor (c) a rain sensor (d) a soil moisture sensor
31. 31.💡 An LED is joined to a 5 V battery through a 470 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) lights up (b) does not light (c) may burn out
32. 32.⚡ Power tells us … (a) the size of a cell (b) the colour of light (c) energy used each second (d) the length of a wire
33. 33.🌈 A resistor has the colour bands violet, black, orange. What is its value (in ohms)?
34. 34.Which drawing is the symbol for a switch? (a) a line lifted at a gap (b) two or more cell symbols (c) a straight line (d) a circle with a cross
35. 35.Which of these uses electricity? (a) a cell (b) a washing machine (c) a generator (d) a wind turbine
36. 36.True or false: a water heater mainly gives out light. (a) False (b) True
37. 37.🔋 What is a battery? (a) a kind of bulb (b) one single wire (c) two or more cells joined (d) a switch with a lid
38. 38.🧮 Resistors of 220 Ω and 47 Ω are joined in series. What is the total resistance (in ohms)?
39. 39.⚡ Which formula gives electric power? (a) P = V × I (b) P = V ÷ I (c) P = I ÷ V (d) P = V + I
40. 40.💡 6 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 4 is taken out of its holder. How many bulbs glow?

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