Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 614 · 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 distance sensor? (a) water a dry plant (b) open blinds at sunrise (c) close a window in rain (d) make a parking alarm
2. 2.🤖 if (light < 400 OR motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 390 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
3. 3.🔍 Which is the odd one out? (a) the fan starts (b) a motion sensor signal (c) a light level reading (d) a button press
4. 4.🔺 A 15 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
5. 5.🔍 Which is the odd one out? (a) an electric drill (b) a mixer grinder (c) an exhaust fan (d) a siren
6. 6.Which of these mainly gives out light? (a) an electric kettle (b) a room heater (c) a tube light (d) a school bell
7. 7.True or false: a laptop runs many apps at once. (a) False (b) True
8. 8.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 350 ms }
   How many times does the LED blink in 9 seconds?
9. 9.✏️ In a circuit diagram, wires are usually drawn as … (a) straight lines (b) wavy lines (c) little stars (d) dotted circles
10. 10.⚡ Which formula gives electric power? (a) P = V + I (b) P = I ÷ V (c) P = V ÷ I (d) P = V × I
11. 11.True or false: triangle, bar and arrows is the symbol for an LED. (a) True (b) False
12. 12.True or false: to fly kites in open fields is not safe. (a) True (b) False
13. 13.🔍 Which is the odd one out? (a) a toaster (b) a street light (c) a tube light (d) a torch
14. 14.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 11 Ω resistor? (a) red-brown-black (b) brown-red-black (c) brown-brown-brown (d) brown-brown-black
15. 15.🔘 A bulb and a cell are joined through 4 switches one after another in a single loop (series). What is the smallest number of switches that must be ON to light the bulb?
16. 16.True or false: on an LED, the shorter leg is the cathode (−). (a) True (b) False
17. 17.⏱️ How many milliseconds are in 1 second? (a) 100 (b) 10 (c) 60 (d) 1000
18. 18.What does a potentiometer do? (a) makes things spin (b) blows if current is high (c) stores a little charge (d) is a resistance knob
19. 19.🧾 A family uses 190 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
20. 20.🔘 Which kind of switch stays where you flip it? (a) a push button (b) a reed switch (c) a toggle switch (d) a tilt switch
21. 21.🔢 To plan an electronics project, what comes right after “list inputs and outputs”? (a) test it and fix it (b) build it with an adult (c) draw the circuit diagram (d) pick a problem to solve
22. 22.What does a slide switch do? (a) springs back when let go (b) flips up or down (c) slides side to side (d) stays where you flip it
23. 23.Which of these is not an IoT device? (a) an app-controlled bulb (b) a plain wall switch (c) a Wi-Fi smart plug (d) a fitness band with app
24. 24.💡 A battery lights 5 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) the same (b) dimmer (c) brighter
25. 25.⏱️ What does “wait 500 ms” do? (a) blinks 500 times (b) turns the LED off (c) pauses for half a second (d) waits 500 seconds
26. 26.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a steel spoon across the gap. Does the bulb glow? (a) Yes (b) No
27. 27.Which of these is safe? (a) keep drinks far away (b) use a cable with cuts (c) fly a kite near wires (d) use mains for a project
28. 28.📶 How many states can a digital pin have? (a) ten (b) one (c) a thousand (d) two
29. 29.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 watt (c) 1 ampere (d) 1 kilowatt-hour (kWh)
30. 30.🧮 A 33 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)?
31. 31.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
32. 32.Which of these means the circuit is closed? (a) the switch is ON (b) the switch is OFF (c) a cell is taken out (d) a wire has come loose
33. 33.🧩 Which component glows using little power? (a) LDR (b) thermistor (c) buzzer (d) LED
34. 34.🤖 When the main loop of a microcontroller program ends, what happens? (a) it stops forever (b) the board breaks (c) it starts again (d) it deletes itself
35. 35.🌈 A resistor has the colour bands brown, green, red. What is its value in kilo-ohms (kΩ)? =
36. 36.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 2400 Ω resistor? (a) red-yellow-brown (b) red-yellow-orange (c) red-yellow-red (d) yellow-red-red
37. 37.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to an 8 V supply. What current flows (in mA)?
38. 38.🔁 count = 4
    while (count < 10) { count = count + 3 }
    How many times does the loop run?
39. 39.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
40. 40.🔺 A current of 40 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =

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