Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 584 · 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 (light < 400 AND motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 330 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
2. 2.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 64 Ω resistor? (a) yellow-blue-black (b) blue-yellow-brown (c) violet-yellow-black (d) blue-yellow-black
3. 3.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
4. 4.⏱️ What does “wait 500 ms” do? (a) waits 500 seconds (b) blinks 500 times (c) turns the LED off (d) pauses for half a second
5. 5.True or false: a torch mainly makes sound. (a) True (b) False
6. 6.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
7. 7.Which of these uses electricity? (a) a cell (b) a television (c) a generator (d) a wind turbine
8. 8.🔐 Is it a good or a risky habit to keep factory passwords? (a) good habit (b) risky habit
9. 9.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V + I (d) P = V × I
10. 10.🤖 if (sound > 60) { red LED ON } else { green LED ON }
    The sound sensor reads 77. What happens? (a) red LED ON (b) green LED ON
11. 11.🔍 Which is the odd one out? (a) a safety pin (b) a copper wire (c) a metal paper clip (d) a wooden stick
12. 12.🤖 if (light < 300) { lamp ON } else { lamp OFF }
    The light sensor reads 378. What happens? (a) lamp ON (b) lamp OFF
13. 13.🌐 Is a plain wall switch an IoT device? (a) an IoT device (b) not an IoT device
14. 14.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 34 Ω resistor? (a) yellow-yellow-black (b) orange-yellow-black (c) orange-yellow-brown (d) yellow-orange-black
15. 15.Which of these is safe? (a) build with an adult near (b) throw cells in a fire (c) touch a switch when wet (d) climb an electric pole
16. 16.True or false: to use daylight to read saves electricity. (a) True (b) False
17. 17.Which job is done by the voltage regulator? (a) shows the board is on (b) keeps the voltage steady (c) restarts the program (d) brings power and code
18. 18.🔍 Which is the odd one out? (a) a plastic ruler (b) a dry cork (c) aluminium foil (d) a glass marble
19. 19.🔺 A 2.5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
20. 20.🔌 Is a turning knob an input or an output for a microcontroller? (a) output (b) input
21. 21.⚡ A device works on 9 V and takes 1.5 A. What is its power (in watts)? =
22. 22.Which of these is an output? (a) a servo motor (b) a sound sensor (c) a push button (d) a keypad
23. 23.🤖 if (light < 400 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 340 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
24. 24.🔌 Is a graphite rod a conductor or an insulator? (a) an insulator (b) a conductor
25. 25.🔢 To run one loop of a plant-watering program, what comes right after “read the soil sensor”? (a) compare with the limit (b) wait a few seconds (c) switch the pump on/off
26. 26.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) neither part (b) both parts (c) the if part (d) the else part
27. 27.🔁 repeat 3 times { repeat 4 times { beep } }
    How many beeps are there?
28. 28.🔍 Which is the odd one out? (a) climb an electric pole (b) stay away from pylons (c) touch a fallen wire (d) use mains for a project
29. 29.💡 3 identical bulbs are joined in series with a 4.5 V battery (ideal wires). How many volts does each bulb get? =
30. 30.🔺 A current of 20 mA flows when 2.4 V is joined across a resistor. What is its resistance (in ohms)?
31. 31.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
32. 32.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = V + I (c) R = V ÷ I (d) R = I ÷ V
33. 33.Which of these mainly makes sound? (a) a toaster (b) a traffic signal (c) a street light (d) a school bell
34. 34.🤖 if (sound > 60) { red LED ON } else { green LED ON }
    The sound sensor reads 59. What happens? (a) red LED ON (b) green LED ON
35. 35.Which of these is the input? (a) count button presses (b) a light level reading (c) an LED lights up (d) an alert on the phone
36. 36.🔍 Which is the odd one out? (a) log out of shared phones (b) set up with a parent (c) share the Wi-Fi key (d) read app permissions
37. 37.Which job needs a sound sensor? (a) switch on lamps at dusk (b) spot someone walking in (c) start a fan when hot (d) switch on with a clap
38. 38.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
39. 39.🔺 A current of 50 mA flows when 12.5 V is joined across a resistor. What is its resistance (in ohms)?
40. 40.True or false: the ammeter measures current. (a) True (b) False

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