Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 125 · 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.True or false: an LDR senses how bright it is. (a) False (b) True
2. 2.🔐 Is it a good or a risky habit to keep factory passwords? (a) risky habit (b) good habit
3. 3.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I ÷ R (c) V = I × R (d) V = I + R
4. 4.🔍 Which is the odd one out? (a) keep drinks far away (b) use a cable with cuts (c) fly kites in open fields (d) take cells out after use
5. 5.🔺 A current of 50 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
6. 6.🤖 if (sound > 80) { red LED ON } else { green LED ON }
   The sound sensor reads 96. What happens? (a) red LED ON (b) green LED ON
7. 7.Which of these is an output? (a) an LED (b) a keypad (c) a temperature sensor (d) a motion sensor
8. 8.🔺 A current of 3 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
9. 9.🤖 if (sound > 70) { red LED ON } else { green LED ON }
   The sound sensor reads 65. What happens? (a) green LED ON (b) red LED ON
10. 10.True or false: to start a fan when hot, use a rain sensor. (a) True (b) False
11. 11.🌐 Each reading a sensor sends is 50 bytes. How many bytes do 140 readings take?
12. 12.Which of these uses electricity? (a) a solar panel (b) a computer (c) a cell (d) a battery
13. 13.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
14. 14.🌐 What does IoT stand for? (a) Inside of Toys (b) Internet of Talk (c) Input of Tools (d) Internet of Things
15. 15.🔐 Who should decide which smart devices go in a child’s room? (a) nobody at all (b) the app’s adverts (c) a parent or guardian (d) an online stranger
16. 16.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they explode (b) they keep glowing (c) they get dimmer (d) they all go out
17. 17.🤖 What is a microcontroller? (a) a kind of bulb (b) a computer on one chip (c) a big desktop computer (d) a type of battery
18. 18.🔍 Which is the odd one out? (a) touch a fallen wire (b) fly kites in open fields (c) poke things in a socket (d) climb an electric pole
19. 19.🔍 Which is the odd one out? (a) keep drinks far away (b) use small battery cells (c) climb an electric pole (d) fly kites in open fields
20. 20.🤖 if (distance < 10) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 8 cm. What happens? (a) buzzer beeps (b) buzzer is silent
21. 21.True or false: on an LED, the longer leg is the anode (+). (a) True (b) False
22. 22.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) − (negative) (b) + (positive)
23. 23.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 25 % (c) 0 % (d) 50 %
24. 24.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) by Wi-Fi (b) not joined (c) in series (d) in parallel
25. 25.🔌 Is a glass marble a conductor or an insulator? (a) a conductor (b) an insulator
26. 26.💡 In a series circuit, how many paths does the current have? (a) two (b) one for each bulb (c) none (d) one
27. 27.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
28. 28.⏱️ loop forever { LED ON; wait 400 ms; LED OFF; wait 600 ms }
    How many times does the LED blink in 9 seconds?
29. 29.⚡ An 18 W device works on 9 V. What current does it take (in amperes)? =
30. 30.True or false: a slide switch stays where you flip it. (a) True (b) False
31. 31.⚡ A device works on 12 V and takes 2 A. What is its power (in watts)? =
32. 32.🔁 What must there be for a current to flow? (a) a plastic gap (b) a complete loop (c) one loose end (d) a broken path
33. 33.Which of these is safe? (a) touch a switch when wet (b) dry your hands first (c) throw cells in a fire (d) touch a fallen wire
34. 34.🌈 A resistor has the colour bands yellow, yellow, red. What is its value in kilo-ohms (kΩ)? =
35. 35.⚡ A bicycle dynamo changes which kind of energy into electricity? (a) light energy (b) movement energy (c) sound energy (d) chemical energy
36. 36.Which of these usually has a microcontroller inside? (a) a plain wall switch (b) a wind-up toy (c) a smart watch (d) a spinning top
37. 37.True or false: on a cell, “usually the red wire” means the + (positive) end. (a) False (b) True
38. 38.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
39. 39.🤖 if (temperature > 36) { show “Hot” } else if (temperature > 18) { show “Warm” } else { show “Cool” }
    The temperature is 42 °C. What is shown? (a) Warm (b) Hot (c) Cool
40. 40.📶 On a 5 V board, a pin set HIGH gives about … (a) 50 V (b) 230 V (c) 5 V (d) 0 V

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