Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 917 · 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 current of 10 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
2. 2.What does a push button do? (a) slides side to side (b) stays where you flip it (c) flips up or down (d) springs back when let go
3. 3.Which of these is the input? (a) decide if soil is dry (b) check if temp > 30 (c) a light level reading (d) an alert on the phone
4. 4.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) stays the same (c) gets smaller (d) becomes zero
5. 5.🔢 To run one loop of a plant-watering program, which comes first: “switch the pump on/off” or “compare with the limit”? (a) switch the pump on/off (b) compare with the limit
6. 6.True or false: a tilt switch stays where you flip it. (a) True (b) False
7. 7.Which of these is a good habit? (a) install software updates (b) tap unknown app links (c) reuse one password (d) ignore update messages
8. 8.🔌 Is an LED an input or an output for a microcontroller? (a) input (b) output
9. 9.🔍 An object is 255 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
10. 10.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
11. 11.🔁 What does “count = count + 1” do? (a) takes 1 away (b) sets count to 1 (c) prints 1 (d) adds 1 to count
12. 12.💡 Why is house wiring done in parallel? (a) to make bulbs dim (b) to save copper only (c) so all go off together (d) each gets full voltage
13. 13.🔍 Which is the odd one out? (a) share the Wi-Fi key (b) keep factory passwords (c) accept every permission (d) install software updates
14. 14.True or false: a thermistor senses how hot it is. (a) False (b) True
15. 15.⏱️ loop forever { LED ON; wait 550 ms; LED OFF; wait 550 ms }
    How many milliseconds does one blink (ON + OFF) take?
16. 16.🧾 A family uses 120 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
17. 17.🌈 A resistor has the colour bands blue, red, red. What is its value in kilo-ohms (kΩ)? =
18. 18.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a capacitor (c) a buzzer (d) a diode
19. 19.True or false: “a door: open or shut” is an analog signal. (a) True (b) False
20. 20.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) always zero (c) less than either one (d) their sum
21. 21.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the process (b) the input (c) the output (d) the battery
22. 22.💡 3 identical bulbs are in parallel and each bulb has its own switch on its path. 1 of the switches is OFF and the rest are ON. How many bulbs glow?
23. 23.True or false: to use daylight to read saves electricity. (a) False (b) True
24. 24.🌐 A weather station sends one reading every 20 seconds. How many readings does it send in 5 minutes?
25. 25.🔋 6 identical 2 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
26. 26.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
27. 27.What does the actuator do? (a) shows data to you (b) acts on a command (c) stores data online (d) measures the real world
28. 28.🔍 Which is the odd one out? (a) set a strong password (b) post your live location (c) read app permissions (d) share only needed data
29. 29.Which drawing is the symbol for a cell? (a) a long and a short line (b) a circle with M inside (c) many long-short pairs (d) two or more cell symbols
30. 30.🔌 Is a paper strip a conductor or an insulator? (a) an insulator (b) a conductor
31. 31.True or false: to log out of shared phones is a good habit. (a) False (b) True
32. 32.🔋 4 identical 3 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
33. 33.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
34. 34.🌐 How does a home IoT device usually send its data to the app? (a) by shouting (b) over Wi-Fi (c) by post (d) through a candle
35. 35.⏱️ repeat 4 times { buzzer ON; wait 300 ms; buzzer OFF; wait 700 ms }
    How many milliseconds does this take in all?
36. 36.🔍 Which is the odd one out? (a) a soil moisture reading (b) a buzzer beeps (c) a button press (d) a light level reading
37. 37.True or false: on an LED, the longer leg is the cathode (−). (a) False (b) True
38. 38.🧮 Five equal 50 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
39. 39.🔍 Which is the odd one out? (a) a glass marble (b) a plastic ruler (c) a steel spoon (d) a rubber eraser
40. 40.🧩 A capacitor in a circuit can … (a) measure heat (b) make light (c) store charge briefly (d) spin a wheel

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