Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 456 · 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 of these is an output? (a) a push button (b) a light sensor (c) a keypad (d) a speaker
2. 2.True or false: on a cell, “the shorter symbol line” means the + (positive) end. (a) False (b) True
3. 3.🌈 A resistor has the colour bands blue, white, brown. What is its value (in ohms)?
4. 4.True or false: on a cell, “the longer symbol line” means the − (negative) end. (a) False (b) True
5. 5.🔍 Which sensor would you use to open blinds at sunrise? (a) a sound sensor (b) a light sensor (c) a motion sensor (d) a soil moisture sensor
6. 6.Which of these is a conductor? (a) a woollen thread (b) a graphite rod (c) a plastic straw (d) a rubber eraser
7. 7.🔐 Is it a good or a risky habit to tap unknown app links? (a) good habit (b) risky habit
8. 8.🔍 Which sensor would you use to warn of a gas leak? (a) a gas sensor (b) a light sensor (c) a distance sensor (d) a temperature sensor
9. 9.Which of these is the output? (a) a soil moisture reading (b) decide if soil is dry (c) an alert on the phone (d) check if temp > 30
10. 10.⚡ Which formula gives electric power? (a) P = V × I (b) P = V ÷ I (c) P = I ÷ V (d) P = V + I
11. 11.Which of these is an insulator? (a) a safety pin (b) a steel spoon (c) an iron nail (d) a plastic ruler
12. 12.True or false: a dot where wires meet is the symbol for a resistor. (a) True (b) False
13. 13.True or false: power is measured in watts (W). (a) False (b) True
14. 14.🌈 Which band is read first on a resistor? (a) any band (b) the widest gap (c) the one nearest an end (d) the gold band
15. 15.🔁 x = 3
    repeat 3 times { x = x × 2 }
    What is x at the end?
16. 16.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 52 Ω resistor? (a) green-red-brown (b) green-red-black (c) blue-red-black (d) red-green-black
17. 17.Which of these is an IoT device? (a) a fitness band with app (b) a plain wall switch (c) a pencil sharpener (d) a plain table fan
18. 18.💡 A red LED uses 2 V and should get 20 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
19. 19.🔍 Which is the odd one out? (a) leave the TV on standby (b) switch off empty rooms (c) set the AC to 24 °C (d) use daylight to read
20. 20.Which of these is true of a series circuit? (a) one out, the rest glow (b) many paths for current (c) a break stops every bulb (d) used in house wiring
21. 21.✏️ In a circuit diagram, which part is drawn as two or more cell symbols? (a) wire (b) resistor (c) battery (d) ammeter
22. 22.🔁 repeat 5 times { repeat 6 times { beep } }
    How many beeps are there?
23. 23.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V ÷ R (c) I = V × R (d) I = V + R
24. 24.Which job needs a motion sensor? (a) spot someone walking in (b) water a dry plant (c) stop a robot near walls (d) measure classroom noise
25. 25.Which of these saves electricity? (a) leave the TV on standby (b) close the fridge quickly (c) leave fridge door open (d) run fans in empty rooms
26. 26.🤖 When the main loop of a microcontroller program ends, what happens? (a) it deletes itself (b) it starts again (c) it stops forever (d) the board breaks
27. 27.🔌 Is a woollen thread a conductor or an insulator? (a) a conductor (b) an insulator
28. 28.🗺️ In an input → process → output plan, is “count button presses” the input, the process or the output? (a) input (b) process (c) output
29. 29.⏱️ loop forever { LED ON; wait 350 ms; LED OFF; wait 500 ms }
    How many milliseconds does one blink (ON + OFF) take?
30. 30.🔌 Is aluminium foil a conductor or an insulator? (a) a conductor (b) an insulator
31. 31.🌈 In the resistor colour code, which number does orange stand for?
32. 32.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) − (negative) (b) + (positive)
33. 33.🔍 Which is the odd one out? (a) a siren (b) a school bell (c) an LED lamp (d) a doorbell
34. 34.🔍 Which is the odd one out? (a) poke things in a socket (b) fly a kite near wires (c) stop if a part gets hot (d) use mains for a project
35. 35.🧾 A family uses 20 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
36. 36.🧮 Three equal 30 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
37. 37.💡 A blue LED uses 3 V and should get 25 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
38. 38.What does the actuator do? (a) carries the data (b) shows data to you (c) measures the real world (d) acts on a command
39. 39.🔍 An object is 17 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
40. 40.💡 Why is house wiring done in parallel? (a) to make bulbs dim (b) to save copper only (c) each gets full voltage (d) so all go off together

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