Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 329 · 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.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) zero (c) stay the same (d) bigger
2. 2.🔋 A 6 V battery and two 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
3. 3.🌈 Which band is read first on a resistor? (a) the gold band (b) the widest gap (c) any band (d) the one nearest an end
4. 4.🔺 A current of 20 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
5. 5.True or false: on a cell, “the end with a bump” means the + (positive) end. (a) True (b) False
6. 6.True or false: on a cell, “usually the black wire” means the − (negative) end. (a) False (b) True
7. 7.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
   set pin 8 LOW
   set pin 8 HIGH
   set pin 7 LOW
   set pin 8 HIGH
   Is the LED ON or OFF at the end? (a) OFF (b) ON
8. 8.🧩 Which component senses how hot it is? (a) potentiometer (b) resistor (c) thermistor (d) capacitor
9. 9.Which of these is an IoT device? (a) a battery torch (b) a plain wall switch (c) a paper calendar (d) a Wi-Fi smart plug
10. 10.⚠️ Is it safe to build with an adult near? (a) not safe (b) safe
11. 11.True or false: “count button presses” is the input. (a) True (b) False
12. 12.🔺 A current of 25 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
13. 13.Which of these saves electricity? (a) run fans in empty rooms (b) iron one shirt at a time (c) leave fridge door open (d) close the fridge quickly
14. 14.🔢 To run one loop of a plant-watering program, which is the FIRST step? (a) compare with the limit (b) read the soil sensor (c) wait a few seconds (d) switch the pump on/off
15. 15.🧭 Which part of a microcontroller board restarts the program? (a) the reset button (b) the USB port (c) the pins (d) the voltage regulator
16. 16.⚠️ Is it safe to stay away from pylons? (a) safe (b) not safe
17. 17.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V + I (d) P = V × I
18. 18.💡 Why does an LED need a resistor in series? (a) to limit the current (b) to store charge (c) to change its colour (d) to make it brighter
19. 19.✏️ In a circuit diagram, wires are usually drawn as … (a) wavy lines (b) little stars (c) dotted circles (d) straight lines
20. 20.🧮 A 22 Ω resistor is joined in series with two equal 330 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
21. 21.🔌 Is a steel spoon a conductor or an insulator? (a) a conductor (b) an insulator
22. 22.🔍 Which is the odd one out? (a) an electric drill (b) an electric toy car (c) a mixer grinder (d) a night lamp
23. 23.What does a reed switch do? (a) works only while pressed (b) closes near a magnet (c) stays where you flip it (d) closes when tipped over
24. 24.💡 A blue LED uses 3 V and should get 20 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
25. 25.✏️ In a cell symbol, which line is the + terminal? (a) the longer line (b) the shorter line (c) both lines (d) neither line
26. 26.🔁 What must there be for a current to flow? (a) one loose end (b) a complete loop (c) a broken path (d) a plastic gap
27. 27.🤖 if (temperature > 28) { fan ON } else { fan OFF }
    The temperature sensor reads 32 °C. What happens? (a) fan OFF (b) fan ON
28. 28.🗺️ Before building a project, what should you write down first? (a) the box colour (b) nothing at all (c) the final price (d) inputs and outputs
29. 29.What does a tilt switch do? (a) works only while pressed (b) stays where you flip it (c) closes when tipped over (d) springs back when let go
30. 30.🔘 A cell and a bulb are joined to 2 side-by-side paths with one switch on each path — A and B (parallel). A is OFF and B is OFF. Does the bulb glow? (a) No (b) Yes
31. 31.🔘 A cell and a bulb are joined to two side-by-side paths: path 1 has switches A and B one after another, path 2 has switch C. A is OFF, B is ON and C is ON. Does the bulb glow? (a) No (b) Yes
32. 32.🔋 What should you do with used-up cells? (a) bury them in soil (b) cut them open (c) give them for recycling (d) throw them in a fire
33. 33.Which of these is the input? (a) count button presses (b) decide if soil is dry (c) an LED lights up (d) a button press
34. 34.True or false: “own switch for each bulb” is true of a parallel circuit. (a) False (b) True
35. 35.🧮 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
36. 36.🤖 if (light < 400 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 200 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
37. 37.🔋 Does a television give electricity or use electricity? (a) gives electricity (b) uses electricity
38. 38.True or false: a toggle switch springs back when let go. (a) True (b) False
39. 39.⚡ A bicycle dynamo changes which kind of energy into electricity? (a) light energy (b) sound energy (c) movement energy (d) chemical energy
40. 40.🔍 Which sensor would you use to spot someone walking in? (a) a motion sensor (b) a gas sensor (c) a distance sensor (d) a soil moisture sensor

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