Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 841 · 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.🔢 To run one loop of a plant-watering program, which is the FIRST step? (a) switch the pump on/off (b) read the soil sensor (c) wait a few seconds (d) compare with the limit
2. 2.🔺 A 2 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
3. 3.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they explode (b) they keep glowing (c) they get dimmer (d) they all go out
4. 4.✏️ In a cell symbol, which line is the + terminal? (a) neither line (b) both lines (c) the shorter line (d) the longer line
5. 5.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
6. 6.🧾 A 500 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
7. 7.🧾 A family uses 200 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
8. 8.🔍 Which is the odd one out? (a) compare with a limit (b) a button press (c) decide if soil is dry (d) check if temp > 30
9. 9.🤖 if (temperature > 33) { show “Hot” } else if (temperature > 21) { show “Warm” } else { show “Cool” }
   The temperature is 15 °C. What is shown? (a) Hot (b) Warm (c) Cool
10. 10.Which of these uses electricity? (a) a bicycle dynamo (b) a mobile phone (c) a generator (d) a cell
11. 11.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
12. 12.🔘 A cell, a bulb and switches A, B and C are joined one after another in a single loop (series). A is ON, B is OFF and C is ON. Does the bulb glow? (a) No (b) Yes
13. 13.Which job needs a distance sensor? (a) keep an incubator warm (b) open blinds at sunrise (c) stop a robot near walls (d) start a fan when hot
14. 14.🔺 A current of 10 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
15. 15.🤖 if (light < 200 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 400 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON
16. 16.True or false: on a cell, “the flat end” means the + (positive) end. (a) True (b) False
17. 17.🤖 if (moisture < 50) { pump ON } else { pump OFF }
    The soil moisture sensor reads 38 %. What happens? (a) pump OFF (b) pump ON
18. 18.True or false: the voltmeter measures voltage. (a) True (b) False
19. 19.🔺 A current of 40 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
20. 20.🔌 Which part of a screwdriver should an electrician hold? (a) the metal tip (b) the steel shaft (c) the bare end (d) the plastic handle
21. 21.💡 A battery lights 4 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) dimmer (b) brighter (c) the same
22. 22.🌐 A weather station sends one reading every 5 seconds. How many readings does it send in 2 minutes?
23. 23.🔍 Which is the odd one out? (a) a soil moisture reading (b) check if temp > 30 (c) a button press (d) a motion sensor signal
24. 24.Which job needs a buzzer? (a) spin a robot’s wheels (b) beep an alarm (c) show a status light (d) show the temperature
25. 25.✏️ In a circuit diagram, which part is drawn as a line lifted at a gap? (a) switch (b) LED (c) cell (d) motor
26. 26.🔘 A cell and a bulb are joined to two side-by-side paths: path 1 has switches A and B one after another, path 2 has switch C. A is OFF, B is ON and C is OFF. Does the bulb glow? (a) Yes (b) No
27. 27.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
28. 28.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in parallel (b) in series (c) by Wi-Fi (d) not joined
29. 29.🔐 Is it a good or a risky habit to share the Wi-Fi key? (a) risky habit (b) good habit
30. 30.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a paper strip across the gap. Does the bulb glow? (a) Yes (b) No
31. 31.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V ÷ I (c) R = V + I (d) R = V × I
32. 32.Which job needs a display? (a) show the temperature (b) spin a robot’s wheels (c) show a status light (d) turn to an exact angle
33. 33.Which of these is an insulator? (a) a brass key (b) a safety pin (c) a graphite rod (d) a rubber band
34. 34.✏️ In a circuit diagram, which part is drawn as many long-short pairs? (a) voltmeter (b) switch (c) battery (d) motor
35. 35.Which job needs a distance sensor? (a) switch on lamps at dusk (b) open blinds at sunrise (c) make a parking alarm (d) start a fan when hot
36. 36.🔺 A current of 25 mA flows when 6.25 V is joined across a resistor. What is its resistance (in ohms)?
37. 37.🧭 Which part of a microcontroller board connect sensors and LEDs? (a) the reset button (b) the voltage regulator (c) the pins (d) the power LED
38. 38.Which of these uses electricity? (a) a television (b) a cell (c) a wind turbine (d) a generator
39. 39.⏱️ loop forever { LED ON; wait 350 ms; LED OFF; wait 150 ms }
    How many times does the LED blink in 7 seconds?
40. 40.🔺 A current of 2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =

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