Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 613 · 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 red LED (it uses 2 V) is joined with a 200 Ω resistor to a 6 V supply. What current flows (in mA)?
2. 2.True or false: “many values in a range” is an analog signal. (a) False (b) True
3. 3.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) not joined (b) by Wi-Fi (c) in series (d) in parallel
4. 4.🤖 if (light < 200) { lamp ON } else { lamp OFF }
   The light sensor reads 227. What happens? (a) lamp OFF (b) lamp ON
5. 5.✏️ In a circuit diagram, which part is drawn as a circle with M inside? (a) wire (b) diode (c) ammeter (d) motor
6. 6.🧩 Which component makes things spin? (a) motor (b) thermistor (c) potentiometer (d) LED
7. 7.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
8. 8.⚠️ A cell gets hot when its + and − ends are joined by a bare wire. What is this called? (a) a safe circuit (b) an open circuit (c) a parallel circuit (d) a short circuit
9. 9.🔌 Is a metal paper clip a conductor or an insulator? (a) an insulator (b) a conductor
10. 10.🔘 Two switches are in series. When does the bulb glow? (a) never (b) when both are OFF (c) when both are ON (d) when either is ON
11. 11.True or false: to touch a switch when wet is not safe. (a) False (b) True
12. 12.🤖 if (light < 400 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 470 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
13. 13.🔍 Which sensor would you use to start a fan when hot? (a) a rain sensor (b) a distance sensor (c) a temperature sensor (d) a motion sensor
14. 14.Which of these is a good habit? (a) post your live location (b) share camera links (c) set up with a parent (d) keep factory passwords
15. 15.True or false: on a cell, “usually the red wire” means the − (negative) end. (a) False (b) True
16. 16.🔋 2 identical 3 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
17. 17.🔢 To run one loop of a plant-watering program, what comes right after “read the soil sensor”? (a) compare with the limit (b) switch the pump on/off (c) wait a few seconds
18. 18.⚡ What does a water heater mainly change electricity into? (a) light (b) heat (c) movement (d) sound
19. 19.🔺 In the V-I-R triangle, how do we find R? (a) R = V ÷ I (b) R = I ÷ V (c) R = V × I (d) R = V + I
20. 20.⚡ A device works on 9 V and takes 0.1 A. What is its power (in watts)? =
21. 21.Which of these is a conductor? (a) an iron nail (b) a wooden stick (c) a ceramic cup (d) a plastic ruler
22. 22.🔘 A cell, a bulb and switches A and B are joined one after another in a single loop (series). A is OFF and B is ON. Does the bulb glow? (a) Yes (b) No
23. 23.True or false: on a cell, “the flat end” means the + (positive) end. (a) False (b) True
24. 24.💡 An LED is joined to a 5 V battery with no resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) lights up (c) may burn out
25. 25.🔁 count = 0
    repeat 4 times { count = count + 8 }
    What is count at the end?
26. 26.📶 A pin set LOW gives about … (a) 5 V (b) 0 V (c) 9 V (d) 1.5 V
27. 27.⚡ What does a room heater mainly change electricity into? (a) light (b) heat (c) sound (d) movement
28. 28.Which of these is true of a parallel circuit? (a) a single current path (b) one out, the rest glow (c) one bulb out, all go out (d) a break stops every bulb
29. 29.🔗 Series or parallel circuit: “one out, the rest glow”? (a) series (b) parallel
30. 30.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF
31. 31.Which of these usually has a microcontroller inside? (a) a spinning top (b) a bicycle bell (c) a candle (d) a digital alarm clock
32. 32.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
33. 33.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
34. 34.⏱️ loop forever { LED ON; wait 300 ms; LED OFF; wait 200 ms }
    How many times does the LED blink in 1 second?
35. 35.⚡ A 1.2 W device works on 6 V. What current does it take (in amperes)? =
36. 36.Which of these mainly gives out light? (a) a ceiling fan (b) a table fan (c) a night lamp (d) a doorbell
37. 37.💡 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)?
38. 38.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) − (negative) (b) + (positive)
39. 39.🤖 if (sound > 70) { red LED ON } else { green LED ON }
    The sound sensor reads 59. What happens? (a) red LED ON (b) green LED ON
40. 40.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?

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