Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 228 · 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 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 short circuit (d) a parallel circuit
2. 2.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a diode (c) a buzzer (d) a resistor
3. 3.True or false: to throw cells in a fire is safe. (a) True (b) False
4. 4.⏱️ How many milliseconds are in 1 second? (a) 60 (b) 10 (c) 100 (d) 1000
5. 5.💡 Why is house wiring done in parallel? (a) to make bulbs dim (b) so all go off together (c) to save copper only (d) each gets full voltage
6. 6.Which of these mainly gives out heat? (a) an LED lamp (b) a mixer grinder (c) a rice cooker (d) a school bell
7. 7.🧮 An 11 V battery is joined to 5 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
8. 8.📏 Which unit measures the push of a cell? (a) ohm (Ω) (b) ampere (A) (c) volt (V) (d) watt (W)
9. 9.🌐 Each reading a sensor sends is 25 bytes. How many bytes do 200 readings take?
10. 10.🔺 A current of 50 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
11. 11.Which of these is measured in watts (W)? (a) the push of a cell (b) power (c) voltage (d) how much a part resists
12. 12.What does a diode do? (a) lets current go one way (b) senses how bright it is (c) is a resistance knob (d) glows using little power
13. 13.What does a transistor do? (a) boosts a small signal (b) lets current go one way (c) stores a little charge (d) blows if current is high
14. 14.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they keep glowing (b) they all go out (c) they get dimmer (d) they explode
15. 15.Which of these is measured in amperes (A)? (a) resistance (b) power (c) the flow of charge (d) voltage
16. 16.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) none (c) only one (d) both of them
17. 17.✏️ In a circuit diagram, wires are usually drawn as … (a) dotted circles (b) straight lines (c) little stars (d) wavy lines
18. 18.Which of these is not an IoT device? (a) a Wi-Fi smart plug (b) an app-controlled bulb (c) a Wi-Fi weather station (d) a plain table fan
19. 19.What does a toggle switch do? (a) works only while pressed (b) closes when tipped over (c) springs back when let go (d) flips up or down
20. 20.🔍 Which sensor would you use to close a window in rain? (a) a rain sensor (b) a distance sensor (c) a soil moisture sensor (d) a light sensor
21. 21.📶 On a 5 V board, a pin set HIGH gives about … (a) 0 V (b) 230 V (c) 50 V (d) 5 V
22. 22.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
23. 23.⚠️ Which power source should children use for electronics projects? (a) a mains extension board (b) an inverter socket (c) a wall socket (d) a small battery pack
24. 24.🔺 A 20 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
25. 25.⏱️ How many milliseconds is a wait of 1.4 seconds?
26. 26.🔢 To get a sensor reading onto a phone, which comes first: “the board reads it” or “the sensor measures”? (a) the board reads it (b) the sensor measures
27. 27.True or false: a brass key is a conductor. (a) False (b) True
28. 28.Which of these means the circuit is open? (a) the switch is ON (b) a wire has come loose (c) the loop is complete (d) all wires are joined
29. 29.🔁 x = 5
    repeat 5 times { x = x × 2 }
    What is x at the end?
30. 30.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 8 LOW
    set pin 8 LOW
    Is the LED ON or OFF at the end? (a) OFF (b) ON
31. 31.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
32. 32.Which of these saves electricity? (a) leave fridge door open (b) run fans in empty rooms (c) leave the TV on standby (d) set the AC to 24 °C
33. 33.🤖 “if (A AND B)” is true when … (a) only B is true (b) both A and B are true (c) only A is true (d) both are false
34. 34.True or false: “a break stops every bulb” is true of a parallel circuit. (a) True (b) False
35. 35.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 25 % (c) 5 % (d) 0 %
36. 36.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in parallel (b) not joined (c) by Wi-Fi (d) in series
37. 37.🔢 To run one loop of a plant-watering program, which is the FIRST step? (a) switch the pump on/off (b) compare with the limit (c) read the soil sensor (d) wait a few seconds
38. 38.🌐 In an IoT system, which part stores data online? (a) microcontroller (b) phone app (c) cloud server (d) sensor
39. 39.Which of these mainly gives out heat? (a) a torch (b) an electric iron (c) a loudspeaker (d) a night lamp
40. 40.Which of these saves electricity? (a) switch off empty rooms (b) leave the TV on standby (c) iron one shirt at a time (d) run fans in empty rooms

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