Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 11 · 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 5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
2. 2.🔍 For a microcontroller, is a sensor an input or an output? (a) a power source (b) a fuse (c) an output (d) an input
3. 3.True or false: on a cell, “the longer symbol line” means the + (positive) end. (a) True (b) False
4. 4.🗺️ In an input → process → output plan, is “a motion sensor signal” the input, the process or the output? (a) output (b) input (c) process
5. 5.⚠️ Which power source should children use for electronics projects? (a) an inverter socket (b) a mains extension board (c) a small battery pack (d) a wall socket
6. 6.🔗 Series or parallel circuit: “used in house wiring”? (a) series (b) parallel
7. 7.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a wooden stick. Does the bulb glow? (a) Yes (b) No
8. 8.⚡ A 5 W device works on 5 V. What current does it take (in amperes)? =
9. 9.💡 3 identical bulbs are in parallel and each one takes 1 A. What total current (in amperes) comes from the battery? =
10. 10.🔍 Which is the odd one out? (a) close the fridge quickly (b) use daylight to read (c) unplug idle chargers (d) run fans in empty rooms
11. 11.🤖 if (sound > 70) { red LED ON } else { green LED ON }
    The sound sensor reads 75. What happens? (a) red LED ON (b) green LED ON
12. 12.Which job needs a servo motor? (a) show a status light (b) turn to an exact angle (c) beep an alarm (d) show the temperature
13. 13.🔺 A current of 10 mA flows when 3.3 V is joined across a resistor. What is its resistance (in ohms)?
14. 14.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 4.25 V supply. What current flows (in mA)?
15. 15.🌈 Which band is read first on a resistor? (a) the widest gap (b) the one nearest an end (c) the gold band (d) any band
16. 16.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 50 % (c) 25 % (d) 5 %
17. 17.True or false: a buzzer smooths a wobbly supply. (a) True (b) False
18. 18.🤖 Microcontroller or laptop: which one needs much more power? (a) laptop (b) microcontroller
19. 19.🔍 Which is the odd one out? (a) decide if soil is dry (b) an alert on the phone (c) compare with a limit (d) check if temp > 30
20. 20.⚡ A device works on 12 V and takes 2 A. What is its power (in watts)? =
21. 21.🌈 In the resistor colour code, which number does orange stand for?
22. 22.🔁 What does a variable do in a program? (a) stores a value (b) measures light (c) joins two wires (d) blinks an LED
23. 23.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
24. 24.🔋 Does a cell give electricity or use electricity? (a) uses electricity (b) gives electricity
25. 25.🤖 if (temperature > 30) { fan ON } else { fan OFF }
    The temperature sensor reads 26 °C. What happens? (a) fan ON (b) fan OFF
26. 26.⏱️ How many milliseconds is a wait of 2.5 seconds?
27. 27.Which of these is not safe? (a) dry your hands first (b) poke things in a socket (c) stop if a part gets hot (d) use small battery cells
28. 28.🔺 A 6 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
29. 29.🔁 count = 1
    repeat 5 times { count = count + 6 }
    What is count at the end?
30. 30.🔌 Is a glass marble a conductor or an insulator? (a) an insulator (b) a conductor
31. 31.⏱️ How many milliseconds is a wait of 1.4 seconds?
32. 32.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
33. 33.🧮 Resistors of 68 Ω, 470 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?
34. 34.🔺 A current of 2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
35. 35.⚠️ Is it safe to poke things in a socket? (a) safe (b) not safe
36. 36.🔍 Which sensor would you use to make a parking alarm? (a) a soil moisture sensor (b) a distance sensor (c) a motion sensor (d) a temperature sensor
37. 37.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets bigger (d) gets smaller
38. 38.True or false: a water heater mainly makes movement. (a) False (b) True
39. 39.🧩 A capacitor in a circuit can … (a) make light (b) spin a wheel (c) measure heat (d) store charge briefly
40. 40.🔁 count = 5
    while (count < 17) { count = count + 2 }
    How many times does the loop run?

Free electronics lessons, practice and worksheets at talentjr.in/electronics-for-kids