Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 529 · 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 bicycle dynamo changes which kind of energy into electricity? (a) movement energy (b) light energy (c) sound energy (d) chemical energy
2. 2.🧩 Which component senses how hot it is? (a) potentiometer (b) thermistor (c) diode (d) motor
3. 3.Which of these mainly makes movement? (a) a street light (b) a siren (c) an electric iron (d) a table fan
4. 4.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
5. 5.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) gets smaller (c) gets bigger (d) stays the same
6. 6.⚡ A 13.5 W device works on 9 V. What current does it take (in amperes)? =
7. 7.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
   set pin 7 HIGH
   set pin 8 LOW
   set pin 8 HIGH
   Is the LED ON or OFF at the end? (a) OFF (b) ON
8. 8.🌈 A resistor has the colour bands grey, green, orange. What is its value in kilo-ohms (kΩ)? =
9. 9.True or false: a toggle switch slides side to side. (a) True (b) False
10. 10.🧮 A 150 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)?
11. 11.⏱️ A program says “wait 1750 ms”. How many seconds is that? =
12. 12.🔋 How many 3 V cells must be joined in series to give 18 V?
13. 13.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is OFF (c) a cell is taken out (d) all wires are joined
14. 14.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
15. 15.🔁 x = 5
    repeat 4 times { x = x × 2 }
    What is x at the end?
16. 16.🔍 Which sensor would you use to switch on lamps at dusk? (a) a temperature sensor (b) a sound sensor (c) a light sensor (d) a soil moisture sensor
17. 17.🔢 To plan an electronics project, which comes first: “build it with an adult” or “test it and fix it”? (a) test it and fix it (b) build it with an adult
18. 18.📏 Which unit measures power? (a) ampere (A) (b) volt (V) (c) ohm (Ω) (d) watt (W)
19. 19.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a resistor (c) a motor (d) an LED
20. 20.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
21. 21.🔗 Series or parallel circuit: “many paths for current”? (a) series (b) parallel
22. 22.Which of these usually has a microcontroller inside? (a) a washing machine (b) a spinning top (c) a wind-up toy (d) a hand pump
23. 23.True or false: “a button: pressed or not” is an analog signal. (a) True (b) False
24. 24.🔋 Does a cell give electricity or use electricity? (a) gives electricity (b) uses electricity
25. 25.True or false: the ammeter is joined in series. (a) True (b) False
26. 26.💡 An LED is joined to a 6 V battery through a 470 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) may burn out (b) does not light (c) lights up
27. 27.True or false: “each gets the full volts” is true of a series circuit. (a) True (b) False
28. 28.💡 4 identical bulbs are joined in series with a 12 V battery (ideal wires). How many volts does each bulb get? =
29. 29.✏️ In a circuit diagram, which part is drawn as a circle with an X in it? (a) capacitor (b) wire (c) battery (d) bulb
30. 30.🔁 total = 0
    for i = 1 to 12 { total = total + i }
    What is total at the end?
31. 31.Which of these gives us electricity? (a) a mobile phone (b) a refrigerator (c) a solar panel (d) an air conditioner
32. 32.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is ON (d) a cell is taken out
33. 33.🤖 if (light < 300 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 620 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
34. 34.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
35. 35.🤖 if (temperature > 34) { show “Hot” } else if (temperature > 22) { show “Warm” } else { show “Cool” }
    The temperature is 41 °C. What is shown? (a) Cool (b) Warm (c) Hot
36. 36.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) − (negative) (b) + (positive)
37. 37.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
38. 38.🔋 6 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)? =
39. 39.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 750 Ω resistor? (a) violet-green-black (b) violet-green-brown (c) violet-green-red (d) green-violet-brown
40. 40.💡 2 identical bulbs are joined in parallel across a 4.5 V battery (ideal wires). How many volts does each bulb get? =

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