Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 12 · 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.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
2. 2.True or false: “each gets the full volts” is true of a parallel circuit. (a) False (b) True
3. 3.⏱️ A program says “wait 4500 ms”. How many seconds is that? =
4. 4.🌈 A resistor has the colour bands red, black, brown. What is its value (in ohms)?
5. 5.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) bigger (c) zero (d) smaller
6. 6.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
7. 7.Which of these mainly gives out light? (a) a water heater (b) a room heater (c) a street light (d) a doorbell
8. 8.Which of these is a conductor? (a) a plastic ruler (b) a rubber band (c) a metal paper clip (d) a wooden stick
9. 9.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a safety pin across the gap. Does the bulb glow? (a) No (b) Yes
10. 10.✏️ In a circuit diagram, which part is drawn as a plain rectangle? (a) motor (b) resistor (c) diode (d) cell
11. 11.⚙️ Which actuator would you use to move water to plants? (a) a display (b) a motor (c) a servo motor (d) a pump
12. 12.🧾 A family uses 50 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
13. 13.💡 A battery lights 5 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) dimmer (b) brighter (c) the same
14. 14.Which job needs a motor? (a) beep an alarm (b) spin a robot’s wheels (c) open a gate to 90° (d) move water to plants
15. 15.Which of these is the output? (a) compare with a limit (b) the pump turns on (c) a soil moisture reading (d) a light level reading
16. 16.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
17. 17.🔍 Which is the odd one out? (a) keep factory passwords (b) share only needed data (c) tap unknown app links (d) share camera links
18. 18.🔁 What does a variable do in a program? (a) joins two wires (b) measures light (c) stores a value (d) blinks an LED
19. 19.⏱️ loop forever { LED ON; wait 350 ms; LED OFF; wait 300 ms }
    How many milliseconds does one blink (ON + OFF) take?
20. 20.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 2600 Ω resistor? (a) red-blue-red (b) red-blue-brown (c) red-blue-orange (d) blue-red-red
21. 21.Which job needs a servo motor? (a) move water to plants (b) beep an alarm (c) spin a robot’s wheels (d) turn to an exact angle
22. 22.What does a thermistor do? (a) makes things spin (b) turns a fan or wheels (c) stores a little charge (d) senses how hot it is
23. 23.True or false: an iron nail is an insulator. (a) False (b) True
24. 24.🔺 In the V-I-R triangle, how do we find R? (a) R = V ÷ I (b) R = I ÷ V (c) R = V + I (d) R = V × I
25. 25.🤖 if (distance < 20) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 21 cm. What happens? (a) buzzer beeps (b) buzzer is silent
26. 26.True or false: a torch mainly makes movement. (a) True (b) False
27. 27.What does a toggle switch do? (a) works only while pressed (b) stays where you flip it (c) slides side to side (d) springs back when let go
28. 28.🔺 A 20 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
29. 29.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) + (positive) (b) − (negative)
30. 30.True or false: a push button springs back when let go. (a) True (b) False
31. 31.🔺 A current of 3 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
32. 32.True or false: “bulbs share the voltage” is true of a parallel circuit. (a) True (b) False
33. 33.💡 2 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 2 is taken out of its holder. Does bulb 1 glow? (a) Yes (b) No
34. 34.Which of these is measured in volts (V)? (a) the push of a cell (b) current (c) power (d) resistance
35. 35.⚡ What do we call a flow of electric charge through a wire? (a) sound (b) friction (c) a magnet (d) electric current
36. 36.💡 6 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 5 is taken out of its holder. How many bulbs glow?
37. 37.🔺 A 4.7 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
38. 38.💡 In a series circuit, how many paths does the current have? (a) one for each bulb (b) two (c) none (d) one
39. 39.⚡ A device works on 9 V and takes 3 A. What is its power (in watts)? =
40. 40.⚡ A bicycle dynamo changes which kind of energy into electricity? (a) light energy (b) chemical energy (c) sound energy (d) movement energy

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