Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 354 · 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.🤖 if (temperature > 33) { show “Hot” } else if (temperature > 20) { show “Warm” } else { show “Cool” }
   The temperature is 24 °C. What is shown? (a) Cool (b) Warm (c) Hot
2. 2.🔺 A current of 3 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
3. 3.💡 5 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 1 is taken out of its holder. Does bulb 3 glow? (a) No (b) Yes
4. 4.True or false: a steel coin is an insulator. (a) True (b) False
5. 5.🌈 Which band is read first on a resistor? (a) any band (b) the one nearest an end (c) the widest gap (d) the gold band
6. 6.🔺 A current of 50 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
7. 7.Which of these is safe? (a) touch a switch when wet (b) use a cable with cuts (c) stop if a part gets hot (d) fly a kite near wires
8. 8.⏱️ repeat 5 times { buzzer ON; wait 1000 ms; buzzer OFF; wait 100 ms }
   How many milliseconds does this take in all?
9. 9.💡 An LED is joined to a 3 V battery through a 330 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) lights up (c) may burn out
10. 10.🔍 Which is the odd one out? (a) a brass key (b) a cotton thread (c) a rubber eraser (d) a plastic straw
11. 11.🔺 A current of 10 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
12. 12.🔁 x = 1
    repeat 1 time { x = x × 2 }
    What is x at the end?
13. 13.True or false: one tall, one short bar is the symbol for a capacitor. (a) True (b) False
14. 14.Which job needs a temperature sensor? (a) start a fan when hot (b) stop a robot near walls (c) measure classroom noise (d) close a window in rain
15. 15.🔺 A current of 20 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
16. 16.✏️ Why do engineers draw circuits with symbols? (a) to hide the circuit (b) to make it colourful (c) symbols are heavier (d) quick and clear for all
17. 17.🔘 Which kind of switch closes near a magnet? (a) a tilt switch (b) a reed switch (c) a toggle switch (d) a slide switch
18. 18.💡 3 identical bulbs are joined in series with a 7.5 V battery (ideal wires). How many volts does each bulb get? =
19. 19.🔋 Cells joined + to − in a row (series) give … (a) a bigger voltage (b) a smaller voltage (c) no voltage (d) the same voltage
20. 20.🌐 A weather station sends one reading every 60 seconds. How many readings does it send in 5 minutes?
21. 21.🧩 Which part changes electrical energy into sound? (a) a diode (b) a capacitor (c) a resistor (d) a buzzer
22. 22.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. Does the bulb glow? (a) No (b) Yes
23. 23.🌈 A resistor has the colour bands red, violet, red. What is its value in kilo-ohms (kΩ)? =
24. 24.🔋 What is a battery? (a) one single wire (b) a kind of bulb (c) two or more cells joined (d) a switch with a lid
25. 25.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 4 V supply. What current flows (in mA)?
26. 26.⏱️ How many milliseconds is a wait of 2.4 seconds?
27. 27.True or false: on a cell, “the shorter symbol line” means the − (negative) end. (a) False (b) True
28. 28.🤖 if (temperature > 32) { show “Hot” } else if (temperature > 24) { show “Warm” } else { show “Cool” }
    The temperature is 34 °C. What is shown? (a) Hot (b) Cool (c) Warm
29. 29.Which of these usually has a microcontroller inside? (a) a TV remote (b) a bicycle bell (c) a spinning top (d) a candle
30. 30.Which job needs a distance sensor? (a) switch on lamps at dusk (b) make a parking alarm (c) keep an incubator warm (d) start a fan when hot
31. 31.🔺 A current of 0.25 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
32. 32.🤖 Which is a safe power source for a beginner microcontroller board? (a) a wall socket directly (b) a 230 V cable (c) bare mains wires (d) USB or a 9 V battery
33. 33.🔺 A 2.5 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
34. 34.🔺 A 1.5 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
35. 35.🗺️ In an input → process → output plan, is “a soil moisture reading” the input, the process or the output? (a) output (b) process (c) input
36. 36.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in parallel (b) by Wi-Fi (c) not joined (d) in series
37. 37.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) both parts (b) neither part (c) the if part (d) the else part
38. 38.🤖 “if (A AND B)” is true when … (a) only A is true (b) both A and B are true (c) only B is true (d) both are false
39. 39.⚡ What does a water heater mainly change electricity into? (a) movement (b) sound (c) light (d) heat
40. 40.🔍 A distance sensor sends a sound pulse and hears the echo 16 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?

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