Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 700 · 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.🔐 Is it a good or a risky habit to share the Wi-Fi key? (a) risky habit (b) good habit
2. 2.💡 5 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 4 glow? (a) Yes (b) No
3. 3.🤖 if (distance < 30) { buzzer beeps } else { buzzer is silent }
   The distance sensor reads 23 cm. What happens? (a) buzzer is silent (b) buzzer beeps
4. 4.🔘 A bulb and a cell are joined through 3 switches one after another in a single loop (series). What is the smallest number of switches that must be ON to light the bulb?
5. 5.What does a transistor do? (a) limits the current (b) makes things spin (c) boosts a small signal (d) lets current go one way
6. 6.⚡ A device works on 12 V and takes 3 A. What is its power (in watts)? =
7. 7.🔦 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) Yes (b) No
8. 8.🧮 Two resistors in parallel give a total that is … (a) always zero (b) their sum (c) more than either one (d) less than either one
9. 9.🔍 Which is the odd one out? (a) open a phone charger (b) climb an electric pole (c) use small battery cells (d) touch a switch when wet
10. 10.🌈 A resistor has the colour bands yellow, blue, brown. What is its value (in ohms)?
11. 11.Which of these is an IoT device? (a) a wind-up clock (b) a Wi-Fi doorbell camera (c) a paper calendar (d) a plain table fan
12. 12.✏️ In a circuit diagram, wires are usually drawn as … (a) dotted circles (b) straight lines (c) wavy lines (d) little stars
13. 13.🧩 Which component limits the current? (a) diode (b) potentiometer (c) resistor (d) capacitor
14. 14.Which of these saves electricity? (a) close the fridge quickly (b) use old filament bulbs (c) leave fridge door open (d) iron one shirt at a time
15. 15.🧮 Two equal 10 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
16. 16.🔢 To run one loop of a plant-watering program, which comes first: “read the soil sensor” or “wait a few seconds”? (a) wait a few seconds (b) read the soil sensor
17. 17.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
18. 18.Which of these is a conductor? (a) a paper strip (b) a steel coin (c) a rubber band (d) a cotton thread
19. 19.🔋 Does a mobile phone give electricity or use electricity? (a) gives electricity (b) uses electricity
20. 20.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
21. 21.True or false: a diode beeps for an alarm. (a) False (b) True
22. 22.Which of these is an output? (a) a temperature sensor (b) a keypad (c) a small display (d) a light sensor
23. 23.💡 In a series circuit, how many paths does the current have? (a) one for each bulb (b) two (c) one (d) none
24. 24.⏱️ A program says “wait 8500 ms”. How many seconds is that? =
25. 25.🧮 A 220 Ω resistor is joined in series with two equal 330 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
26. 26.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) zero (c) bigger (d) smaller
27. 27.True or false: “a single current path” is true of a series circuit. (a) False (b) True
28. 28.🔌 Most metals are good … (a) batteries (b) magnets only (c) conductors (d) insulators
29. 29.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 50 % (c) 0 % (d) 25 %
30. 30.🔺 A current of 40 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
31. 31.🌈 A resistor has the colour bands grey, brown, red. What is its value in kilo-ohms (kΩ)? =
32. 32.🔘 When a switch is ON, the circuit is … (a) broken (b) cut (c) open (d) closed
33. 33.🔺 A current of 25 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
34. 34.🔐 Is it a good or a risky habit to install software updates? (a) risky habit (b) good habit
35. 35.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a buzzer (c) a diode (d) a capacitor
36. 36.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a woollen thread across the gap. Does the bulb glow? (a) No (b) Yes
37. 37.🔋 How many 1.5 V cells must be joined in series to give 9 V?
38. 38.🔺 A current of 1.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
39. 39.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
40. 40.⚠️ Is it safe to take cells out after use? (a) safe (b) not safe

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