Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 471 · 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 red LED (it uses 2 V) is joined with a 200 Ω resistor to a 6 V supply. What current flows (in mA)?
2. 2.🔁 repeat 2 times { repeat 2 times { beep } }
   How many beeps are there?
3. 3.⚙️ Which actuator would you use to open a gate to 90°? (a) a motor (b) a servo motor (c) a pump (d) a display
4. 4.True or false: a capacitor stores a little charge. (a) True (b) False
5. 5.🤖 if (temperature > 31) { show “Hot” } else if (temperature > 19) { show “Warm” } else { show “Cool” }
   The temperature is 21 °C. What is shown? (a) Hot (b) Warm (c) Cool
6. 6.🔺 A current of 20 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
7. 7.Which of these is the process? (a) an LED lights up (b) a button press (c) compare with a limit (d) a temperature reading
8. 8.💡 3 identical bulbs are joined in parallel across a 4.5 V battery (ideal wires). How many volts does each bulb get? =
9. 9.🔍 Which is the odd one out? (a) the pump turns on (b) a buzzer beeps (c) a soil moisture reading (d) the fan starts
10. 10.🔘 A bulb and a cell are joined through 2 switches on 2 side-by-side paths, one switch on each path (parallel). What is the smallest number of switches that must be ON to light the bulb?
11. 11.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) a cell is taken out
12. 12.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) + (positive) (b) − (negative)
13. 13.🧩 Which part changes electrical energy into movement? (a) an LED (b) a motor (c) a resistor (d) a fuse
14. 14.🔁 count = 1
    repeat 3 times { count = count + 9 }
    What is count at the end?
15. 15.🔋 Cells joined + to − in a row (series) give … (a) a smaller voltage (b) the same voltage (c) a bigger voltage (d) no voltage
16. 16.💡 A battery lights 5 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) brighter (b) the same (c) dimmer
17. 17.🔍 Which sensor would you use to keep an incubator warm? (a) a rain sensor (b) a temperature sensor (c) a light sensor (d) a sound sensor
18. 18.🔌 Is a steel coin a conductor or an insulator? (a) an insulator (b) a conductor
19. 19.🌐 What does IoT stand for? (a) Input of Tools (b) Internet of Things (c) Inside of Toys (d) Internet of Talk
20. 20.💡 5 identical bulbs are joined in series with a 5 V battery (ideal wires). How many volts does each bulb get? =
21. 21.🔁 count = 4
    while (count < 36) { count = count + 4 }
    How many times does the loop run?
22. 22.True or false: a spinning top usually has a microcontroller inside. (a) False (b) True
23. 23.🔁 repeat 3 times { repeat 3 times { beep } }
    How many beeps are there?
24. 24.🔋 4 identical 2 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
25. 25.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
26. 26.🌈 Which band is read first on a resistor? (a) the widest gap (b) the gold band (c) any band (d) the one nearest an end
27. 27.True or false: to warn of a gas leak, use a light sensor. (a) False (b) True
28. 28.🔁 count = 0
    repeat 2 times { count = count + 8 }
    What is count at the end?
29. 29.⏱️ How many milliseconds is a wait of 4.2 seconds?
30. 30.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = R ÷ V (c) I = V + R (d) I = V × R
31. 31.🔗 Series or parallel circuit: “own switch for each bulb”? (a) parallel (b) series
32. 32.🧮 A 22 Ω resistor is joined in series with two equal 100 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
33. 33.True or false: on a cell, “usually the red wire” means the + (positive) end. (a) True (b) False
34. 34.Which of these is the output? (a) a motion sensor signal (b) an alert on the phone (c) compare with a limit (d) a soil moisture reading
35. 35.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
36. 36.True or false: “a door: open or shut” is an analog signal. (a) False (b) True
37. 37.🔍 Which is the odd one out? (a) a rice cooker (b) a toaster (c) a night lamp (d) an electric iron
38. 38.🔋 Identical cells side by side (in parallel) give … (a) double the voltage (b) the same voltage (c) no voltage (d) half the voltage
39. 39.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = I × R (c) V = I ÷ R (d) V = R ÷ I
40. 40.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) neither part (b) the else part (c) both parts (d) the if part

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