Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 638 · 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.Which job needs a motor? (a) beep an alarm (b) open a gate to 90° (c) spin a robot’s wheels (d) show a status light
2. 2.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
3. 3.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) + (positive) (b) − (negative)
4. 4.🔍 A distance sensor sends a sound pulse and hears the echo 11 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
5. 5.⏱️ repeat 2 times { buzzer ON; wait 100 ms; buzzer OFF; wait 400 ms }
   How many milliseconds does this take in all?
6. 6.🧾 A family uses 70 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
7. 7.🔺 A current of 0.25 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
8. 8.📏 How many kilowatts (kW) is 2350 W? =
9. 9.🧮 Two equal 10 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
10. 10.🧩 Which component stores a little charge? (a) buzzer (b) potentiometer (c) fuse (d) capacitor
11. 11.📏 In the water-pipe picture of a circuit, resistance is like … (a) the water pressure (b) a bigger tank (c) a narrow pipe (d) the flow of water
12. 12.🔘 Switch A is on the main wire next to the cell and the bulb; then the wire splits into two side-by-side paths, one with switch B and one with switch C. A is ON, B is ON and C is ON. Does the bulb glow? (a) No (b) Yes
13. 13.True or false: a laptop runs many apps at once. (a) False (b) True
14. 14.🤖 Does a digital thermometer usually have a microcontroller inside? (a) Yes (b) No
15. 15.🔗 Series or parallel circuit: “used in house wiring”? (a) series (b) parallel
16. 16.🧾 A family uses 150 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
17. 17.🗺️ Before building a project, what should you write down first? (a) the box colour (b) the final price (c) nothing at all (d) inputs and outputs
18. 18.⏱️ What does “wait 500 ms” do? (a) pauses for half a second (b) blinks 500 times (c) turns the LED off (d) waits 500 seconds
19. 19.🔐 A smart speaker is always listening for its wake word. What is a sensible habit? (a) tell it your passwords (b) put it in the bathroom (c) mute it when not in use (d) let strangers use it
20. 20.🧮 A 47 Ω resistor is joined in series with two equal 1000 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
21. 21.What does the Wi-Fi link do? (a) acts on a command (b) carries the data (c) shows data to you (d) stores data online
22. 22.🔘 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?
23. 23.Which of these is the input? (a) compare with a limit (b) the pump turns on (c) check if temp > 30 (d) a motion sensor signal
24. 24.🔺 A 2 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
25. 25.True or false: an iron nail is an insulator. (a) False (b) True
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.🤖 if (distance < 30) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 33 cm. What happens? (a) buzzer beeps (b) buzzer is silent
28. 28.🌐 Is a battery torch an IoT device? (a) an IoT device (b) not an IoT device
29. 29.💡 Why is house wiring done in parallel? (a) to save copper only (b) so all go off together (c) to make bulbs dim (d) each gets full voltage
30. 30.True or false: “a tilt switch: on or off” is a digital signal. (a) True (b) False
31. 31.True or false: on a cell, “usually the red wire” means the + (positive) end. (a) True (b) False
32. 32.🔍 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)?
33. 33.True or false: triangle, bar and arrows is the symbol for an LED. (a) True (b) False
34. 34.True or false: a transistor turns a fan or wheels. (a) True (b) False
35. 35.📏 In the water-pipe picture of a circuit, current is like … (a) the pipe colour (b) the water pressure (c) a narrow pipe (d) the flow of water
36. 36.🔍 Which is the odd one out? (a) switch off empty rooms (b) leave fridge door open (c) use daylight to read (d) use LED lamps
37. 37.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
38. 38.🤖 Microcontroller or laptop: which one runs one small program? (a) laptop (b) microcontroller
39. 39.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 8 HIGH
    set pin 8 HIGH
    Is the LED ON or OFF at the end? (a) OFF (b) ON
40. 40.⚠️ About how many volts do home sockets in India supply? (a) 9 V (b) 12 V (c) 1.5 V (d) 230 V

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