Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 313 · 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.🧮 Four equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
2. 2.Which of these is not safe? (a) build with an adult near (b) dry your hands first (c) stay away from pylons (d) touch a switch when wet
3. 3.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
   set pin 8 HIGH
   set pin 7 HIGH
   Is the LED ON or OFF at the end? (a) ON (b) OFF
4. 4.🔌 Is a light sensor an input or an output for a microcontroller? (a) input (b) output
5. 5.What does a resistor do? (a) stores a little charge (b) smooths a wobbly supply (c) glows using little power (d) limits the current
6. 6.🤖 “if (A AND B)” is true when … (a) only B is true (b) both A and B are true (c) both are false (d) only A is true
7. 7.🔐 Who should decide which smart devices go in a child’s room? (a) the app’s adverts (b) an online stranger (c) a parent or guardian (d) nobody at all
8. 8.🧩 Which component glows using little power? (a) motor (b) buzzer (c) potentiometer (d) LED
9. 9.🤖 if (light < 200 OR motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 270 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
10. 10.🤖 if (light < 200 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 440 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON
11. 11.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they keep glowing (b) they get dimmer (c) they all go out (d) they explode
12. 12.🌈 A resistor has the colour bands grey, red, orange. What is its value in kilo-ohms (kΩ)? =
13. 13.🔋 2 identical 2 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
14. 14.⚡ Which formula gives electric power? (a) P = V × I (b) P = V ÷ I (c) P = V + I (d) P = I ÷ V
15. 15.🤖 if (temperature > 28) { fan ON } else { fan OFF }
    The temperature sensor reads 27 °C. What happens? (a) fan OFF (b) fan ON
16. 16.🧮 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
17. 17.🔌 Is a motor an input or an output for a microcontroller? (a) input (b) output
18. 18.True or false: “many values in a range” is an analog signal. (a) True (b) False
19. 19.True or false: a diode lets current go one way. (a) True (b) False
20. 20.🌐 Is a plain table fan an IoT device? (a) not an IoT device (b) an IoT device
21. 21.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) use old filament bulbs (c) close the fridge quickly (d) switch off empty rooms
22. 22.Which of these is true of a parallel circuit? (a) bulbs share the voltage (b) a break stops every bulb (c) one out, the rest glow (d) a single current path
23. 23.🌈 A resistor has the colour bands green, orange, black. What is its value (in ohms)?
24. 24.Which of these is an IoT device? (a) a plain wall switch (b) a plain table fan (c) a Wi-Fi doorbell camera (d) a paper calendar
25. 25.🌈 A resistor has the colour bands red, black, black. What is its value (in ohms)?
26. 26.Which of these gives us electricity? (a) a refrigerator (b) a television (c) a solar panel (d) a mobile phone
27. 27.🔺 A current of 1 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
28. 28.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 320 Ω resistor? (a) orange-red-brown (b) orange-red-red (c) orange-red-black (d) red-orange-brown
29. 29.💡 Why does an LED need a resistor in series? (a) to limit the current (b) to store charge (c) to make it brighter (d) to change its colour
30. 30.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
31. 31.True or false: an electric toy car mainly gives out light. (a) True (b) False
32. 32.🤖 Does a smart watch usually have a microcontroller inside? (a) No (b) Yes
33. 33.🔋 How many volts does one ordinary torch cell give? (a) 230 V (b) 0.5 V (c) 1.5 V (d) 15 V
34. 34.Which drawing is the symbol for a switch? (a) a line lifted at a gap (b) a circle with A inside (c) a small empty box (d) one tall, one short bar
35. 35.Which drawing is the symbol for a motor? (a) a small empty box (b) a circle with an X in it (c) a circle with M inside (d) triangle against a bar
36. 36.⏱️ How many milliseconds is a wait of 2.5 seconds?
37. 37.🔁 total = 0
    for i = 1 to 10 { total = total + i }
    What is total at the end?
38. 38.⚡ What does a ceiling fan mainly change electricity into? (a) movement (b) heat (c) light (d) sound
39. 39.Which of these is a conductor? (a) a paper strip (b) a cotton thread (c) aluminium foil (d) a glass marble
40. 40.🔺 A current of 3 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =

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