Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 80 · 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 bicycle dynamo changes which kind of energy into electricity? (a) light energy (b) chemical energy (c) movement energy (d) sound energy
2. 2.🔺 A 5 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
3. 3.💡 A red LED uses 2 V and should get 20 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
4. 4.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
5. 5.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they get dimmer (b) they explode (c) they all go out (d) they keep glowing
6. 6.True or false: a torch mainly gives out light. (a) True (b) False
7. 7.Which of these is the output? (a) check if temp > 30 (b) the pump turns on (c) decide if soil is dry (d) compare with a limit
8. 8.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
9. 9.💡 What happens if an LED is put in backwards? (a) it does not light (b) it makes a sound (c) it changes colour (d) it lights brighter
10. 10.True or false: “a tilt switch: on or off” is a digital signal. (a) False (b) True
11. 11.Which of these is safe? (a) touch a switch when wet (b) use a cable with cuts (c) dry your hands first (d) climb an electric pole
12. 12.⚡ A device works on 3 V and takes 0.5 A. What is its power (in watts)? =
13. 13.🌈 A resistor has the colour bands violet, red, orange. What is its value in kilo-ohms (kΩ)? =
14. 14.True or false: on a cell, “the shorter symbol line” means the − (negative) end. (a) False (b) True
15. 15.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a rubber band across the gap. Does the bulb glow? (a) Yes (b) No
16. 16.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a motor (c) an LED (d) a resistor
17. 17.True or false: an electric iron mainly gives out heat. (a) True (b) False
18. 18.🌈 A resistor has the colour bands green, black, red. What is its value (in ohms)?
19. 19.🔺 A current of 50 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
20. 20.🧩 A capacitor in a circuit can … (a) store charge briefly (b) measure heat (c) make light (d) spin a wheel
21. 21.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) neither part (b) the if part (c) both parts (d) the else part
22. 22.🔋 5 identical 1.2 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
23. 23.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
24. 24.✏️ In a circuit diagram, which part is drawn as one tall, one short bar? (a) resistor (b) ammeter (c) LED (d) cell
25. 25.🔘 Switch A is on the main wire next to the cell and the bulb; then the wire splits into two side-by-side paths, one with switch B and one with switch C. A is OFF, B is OFF and C is OFF. Does the bulb glow? (a) No (b) Yes
26. 26.True or false: the ammeter measures voltage. (a) True (b) False
27. 27.✏️ In a cell symbol, which line is the + terminal? (a) both lines (b) the shorter line (c) the longer line (d) neither line
28. 28.🤖 if (sound > 60) { red LED ON } else { green LED ON }
    The sound sensor reads 41. What happens? (a) green LED ON (b) red LED ON
29. 29.🌈 A resistor has the colour bands red, white, yellow. What is its value in kilo-ohms (kΩ)? =
30. 30.Which of these is a good habit? (a) reuse one password (b) keep factory passwords (c) tap unknown app links (d) install software updates
31. 31.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a capacitor (c) a resistor (d) a diode
32. 32.🌐 A weather station sends one reading every 5 seconds. How many readings does it send in 2 minutes?
33. 33.True or false: on a cell, “the shorter symbol line” means the + (positive) end. (a) True (b) False
34. 34.⚡ Power tells us … (a) the colour of light (b) energy used each second (c) the size of a cell (d) the length of a wire
35. 35.🤖 “if (A AND B)” is true when … (a) both are false (b) both A and B are true (c) only B is true (d) only A is true
36. 36.⚡ Which formula gives electric power? (a) P = V + I (b) P = V × I (c) P = I ÷ V (d) P = V ÷ I
37. 37.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
38. 38.⚠️ About how many volts do home sockets in India supply? (a) 1.5 V (b) 230 V (c) 12 V (d) 9 V
39. 39.🔍 Which sensor would you use to close a window in rain? (a) a soil moisture sensor (b) a distance sensor (c) a sound sensor (d) a rain sensor
40. 40.✏️ In a circuit diagram, wires are usually drawn as … (a) straight lines (b) wavy lines (c) little stars (d) dotted circles

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