Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 77 · 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: to build with an adult near is not safe. (a) False (b) True
2. 2.⚠️ Is it safe to throw cells in a fire? (a) safe (b) not safe
3. 3.🤖 Which is a safe power source for a beginner microcontroller board? (a) USB or a 9 V battery (b) a 230 V cable (c) bare mains wires (d) a wall socket directly
4. 4.Which of these mainly gives out heat? (a) a traffic signal (b) a toaster (c) a street light (d) a doorbell
5. 5.💡 Why does an LED need a resistor in series? (a) to store charge (b) to make it brighter (c) to limit the current (d) to change its colour
6. 6.Which of these means the circuit is closed? (a) the switch is OFF (b) all wires are joined (c) the bulb is unscrewed (d) a wire has come loose
7. 7.Which of these is a good habit? (a) change default passwords (b) share the Wi-Fi key (c) reuse one password (d) share camera links
8. 8.🧭 Which part of a microcontroller board brings power and code? (a) the main chip (b) the reset button (c) the USB port (d) the pins
9. 9.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
10. 10.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) neither part (b) both parts (c) the else part (d) the if part
11. 11.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 49 Ω resistor? (a) yellow-white-brown (b) yellow-white-black (c) green-white-black (d) white-yellow-black
12. 12.🔺 A current of 20 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
13. 13.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the input (b) the output (c) the battery (d) the process
14. 14.🤖 What is a microcontroller? (a) a computer on one chip (b) a big desktop computer (c) a kind of bulb (d) a type of battery
15. 15.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a diode (c) a capacitor (d) a resistor
16. 16.🔺 A 2.2 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
17. 17.What does the sensor do? (a) carries the data (b) measures the real world (c) stores data online (d) shows data to you
18. 18.✏️ In a circuit diagram, which part is drawn as a small empty box? (a) motor (b) cell (c) resistor (d) battery
19. 19.🤖 Does a plain wall switch usually have a microcontroller inside? (a) Yes (b) No
20. 20.🔍 Which is the odd one out? (a) a rubber eraser (b) a plastic straw (c) a woollen thread (d) a metal paper clip
21. 21.✏️ In a circuit diagram, which part is drawn as a circle with an X in it? (a) junction (b) ammeter (c) bulb (d) battery
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: “many paths for current” is true of a series circuit. (a) True (b) False
24. 24.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 volt (c) 1 watt (d) 1 kilowatt-hour (kWh)
25. 25.🔺 A current of 50 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
26. 26.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in series (b) not joined (c) by Wi-Fi (d) in parallel
27. 27.🔺 A 3 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
28. 28.🌐 A soil sensor sends a reading to an app every 5 minutes. How many readings arrive in 4 hours?
29. 29.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
30. 30.True or false: to switch on lamps at dusk, use a soil moisture sensor. (a) False (b) True
31. 31.🤖 if (sound > 80) { red LED ON } else { green LED ON }
    The sound sensor reads 85. What happens? (a) red LED ON (b) green LED ON
32. 32.📏 Which unit measures voltage? (a) watt (W) (b) ohm (Ω) (c) volt (V) (d) ampere (A)
33. 33.🔁 total = 0
    for i = 1 to 11 { total = total + i }
    What is total at the end?
34. 34.⚠️ Is it safe to use small battery cells? (a) not safe (b) safe
35. 35.Which of these is true of a series circuit? (a) one bulb out, all go out (b) many paths for current (c) own switch for each bulb (d) one out, the rest glow
36. 36.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
37. 37.🤖 if (temperature > 31) { show “Hot” } else if (temperature > 22) { show “Warm” } else { show “Cool” }
    The temperature is 12 °C. What is shown? (a) Warm (b) Cool (c) Hot
38. 38.⚡ Power tells us … (a) the length of a wire (b) the size of a cell (c) energy used each second (d) the colour of light
39. 39.Which of these has no microcontroller inside? (a) a TV remote (b) a digital alarm clock (c) a microwave oven (d) a bicycle bell
40. 40.🔘 Two switches are in parallel (side by side). When does the bulb glow? (a) never (b) only when both are ON (c) only when both are OFF (d) when either is ON

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