Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 473 · 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) a buzzer (b) a light sensor (c) a water pump (d) a motor
2. 2.🌈 A resistor has the colour bands blue, brown, black. What is its value (in ohms)?
3. 3.🧮 A 10 Ω resistor is joined in series with two equal 20 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
4. 4.💡 What does LED stand for? (a) large electric dial (b) light energy dial (c) light-emitting diode (d) low energy device
5. 5.🔋 On a cell, does “usually the black wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
6. 6.🔌 Is a cotton thread a conductor or an insulator? (a) an insulator (b) a conductor
7. 7.🔍 Which is the odd one out? (a) use daylight to read (b) unplug idle chargers (c) use LED lamps (d) run fans in empty rooms
8. 8.⏱️ loop forever { LED ON; wait 50 ms; LED OFF; wait 500 ms }
   How many milliseconds does one blink (ON + OFF) take?
9. 9.💡 In a series circuit, how many paths does the current have? (a) none (b) one (c) one for each bulb (d) two
10. 10.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
11. 11.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to store charge (c) to limit the current (d) to make it brighter
12. 12.🔁 total = 0
    for i = 1 to 7 { total = total + i }
    What is total at the end?
13. 13.🔁 What does “count = count + 1” do? (a) takes 1 away (b) prints 1 (c) adds 1 to count (d) sets count to 1
14. 14.✏️ In a circuit diagram, which part is drawn as a circle with a cross? (a) voltmeter (b) bulb (c) resistor (d) junction
15. 15.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V × I (c) R = V ÷ I (d) R = V + I
16. 16.⏱️ How many milliseconds is a wait of 3.5 seconds?
17. 17.🔍 Which is the odd one out? (a) a soil moisture reading (b) an LED lights up (c) the pump turns on (d) a buzzer beeps
18. 18.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a ceramic cup. Does the bulb glow? (a) Yes (b) No
19. 19.Which drawing is the symbol for a battery? (a) two or more cell symbols (b) a dot where wires meet (c) a circle with a cross (d) a circle with M inside
20. 20.🔺 A current of 10 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
21. 21.✏️ In a circuit diagram, which part is drawn as a long and a short line? (a) capacitor (b) cell (c) battery (d) ammeter
22. 22.⚠️ A cell gets hot when its + and − ends are joined by a bare wire. What is this called? (a) a parallel circuit (b) a short circuit (c) a safe circuit (d) an open circuit
23. 23.⚡ What does a tube light mainly change electricity into? (a) light (b) sound (c) heat (d) movement
24. 24.🔋 Does an air conditioner give electricity or use electricity? (a) gives electricity (b) uses electricity
25. 25.🔌 Is a brass key a conductor or an insulator? (a) an insulator (b) a conductor
26. 26.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V + I (c) P = I ÷ V (d) P = V × I
27. 27.🔺 A current of 1.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
28. 28.📏 How many amperes (A) is 350 mA? =
29. 29.⚡ A device works on 24 V and takes 0.1 A. What is its power (in watts)? =
30. 30.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the output (b) the process (c) the input (d) the battery
31. 31.🧩 Which part changes electrical energy into sound? (a) a diode (b) a capacitor (c) a resistor (d) a buzzer
32. 32.⚡ A 6 W device works on 24 V. What current does it take (in amperes)? =
33. 33.🔘 A cell and a bulb are joined to 4 side-by-side paths with one switch on each path — A, B, C and D (parallel). A is OFF, B is ON, C is OFF and D is ON. Does the bulb glow? (a) No (b) Yes
34. 34.Which of these mainly gives out heat? (a) a rice cooker (b) a ceiling fan (c) a traffic signal (d) an electric toy car
35. 35.💡 An LED is joined to a 9 V battery through a 1000 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) may burn out (c) lights up
36. 36.🔋 7 identical 2 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
37. 37.🔋 How many volts does one ordinary torch cell give? (a) 230 V (b) 0.5 V (c) 1.5 V (d) 15 V
38. 38.🤖 if (light < 300 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 90 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
39. 39.True or false: “own switch for each bulb” is true of a series circuit. (a) False (b) True
40. 40.True or false: “used in house wiring” is true of a parallel circuit. (a) True (b) False

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