Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 873 · 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 is the odd one out? (a) an app-controlled bulb (b) a pencil sharpener (c) a smart energy meter (d) a Wi-Fi weather station
2. 2.🔍 A distance sensor sends a sound pulse and hears the echo 6 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
3. 3.✏️ Why do engineers draw circuits with symbols? (a) to make it colourful (b) symbols are heavier (c) to hide the circuit (d) quick and clear for all
4. 4.True or false: “an alert on the phone” is the output. (a) False (b) True
5. 5.🔺 A 0.8 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
6. 6.🔁 count = 4
   repeat 3 times { count = count + 6 }
   What is count at the end?
7. 7.True or false: a paper strip is a conductor. (a) True (b) False
8. 8.🔗 Series or parallel circuit: “many paths for current”? (a) parallel (b) series
9. 9.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the process (b) the input (c) the output (d) the battery
10. 10.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 100 ms }
    How many times does the LED blink in 4 seconds?
11. 11.True or false: a hand pump has no microcontroller inside. (a) False (b) True
12. 12.🔺 A current of 10 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
13. 13.🔋 6 identical 1.2 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
14. 14.🧾 A family uses 140 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
15. 15.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a brass key across the gap. Does the bulb glow? (a) No (b) Yes
16. 16.🔺 A current of 0.2 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
17. 17.⚡ What does a water heater mainly change electricity into? (a) movement (b) sound (c) heat (d) light
18. 18.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = V × I (c) R = I ÷ V (d) R = V ÷ I
19. 19.True or false: to switch off empty rooms wastes electricity. (a) False (b) True
20. 20.🔁 What does “count = count + 1” do? (a) prints 1 (b) adds 1 to count (c) takes 1 away (d) sets count to 1
21. 21.⏱️ How many milliseconds is a wait of 1.6 seconds?
22. 22.🧮 A 68 Ω resistor is joined in series with two equal 50 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
23. 23.🔺 A current of 3 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
24. 24.🔌 Is an iron nail a conductor or an insulator? (a) an insulator (b) a conductor
25. 25.🧾 Which lamp gives the same light for the least power? (a) a candle (b) an oil lamp (c) a filament bulb (d) an LED lamp
26. 26.💡 A red LED uses 2 V and should get 20 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
27. 27.🔍 Which sensor would you use to keep an incubator warm? (a) a temperature sensor (b) a soil moisture sensor (c) a distance sensor (d) a sound sensor
28. 28.Which of these is an insulator? (a) a copper wire (b) a brass key (c) a steel spoon (d) a plastic straw
29. 29.🔍 Which is the odd one out? (a) an app-controlled bulb (b) a Wi-Fi weather station (c) a fitness band with app (d) a wind-up clock
30. 30.⚙️ What is an actuator? (a) a program (b) an output that acts (c) a sensor (d) a battery
31. 31.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) always zero (c) their sum (d) less than either one
32. 32.True or false: a paper strip is an insulator. (a) True (b) False
33. 33.⚡ A 1.25 W device works on 5 V. What current does it take (in amperes)? =
34. 34.Which of these saves electricity? (a) leave fridge door open (b) close the fridge quickly (c) use old filament bulbs (d) leave the TV on standby
35. 35.🔐 Is it a good or a risky habit to set a strong password? (a) risky habit (b) good habit
36. 36.Which of these is measured in watts (W)? (a) voltage (b) energy used each second (c) how much a part resists (d) resistance
37. 37.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V ÷ I (d) P = V × I
38. 38.📏 Which unit measures resistance? (a) volt (V) (b) ohm (Ω) (c) watt (W) (d) ampere (A)
39. 39.💡 In a series circuit, how many paths does the current have? (a) two (b) one (c) one for each bulb (d) none
40. 40.💡 A battery lights 3 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

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