Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 732 · 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.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 700 ms }
   How many milliseconds does one blink (ON + OFF) take?
2. 2.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
3. 3.Which of these is an input? (a) a speaker (b) a buzzer (c) an LED (d) a light sensor
4. 4.True or false: “bulbs share the voltage” is true of a series circuit. (a) True (b) False
5. 5.🔺 A current of 10 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
6. 6.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
7. 7.Which drawing is the symbol for a bulb? (a) one tall, one short bar (b) a long and a short line (c) a circle with a cross (d) a small empty box
8. 8.🔍 Which is the odd one out? (a) set a strong password (b) install software updates (c) tap unknown app links (d) log out of shared phones
9. 9.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a plastic ruler. Does the bulb glow? (a) No (b) Yes
10. 10.🔺 A current of 1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
11. 11.🔍 Which is the odd one out? (a) cover unused cameras (b) read app permissions (c) share camera links (d) log out of shared phones
12. 12.🔢 To run one loop of a plant-watering program, which comes first: “switch the pump on/off” or “compare with the limit”? (a) switch the pump on/off (b) compare with the limit
13. 13.🔘 What does a switch do in a circuit? (a) stores current (b) changes the voltage (c) opens or closes the loop (d) makes electricity
14. 14.🤖 if (light < 300) { lamp ON } else { lamp OFF }
    The light sensor reads 332. What happens? (a) lamp ON (b) lamp OFF
15. 15.🌈 In the resistor colour code, which number does orange stand for?
16. 16.🔌 Is a steel coin a conductor or an insulator? (a) an insulator (b) a conductor
17. 17.💡 An LED is joined to a 5 V battery with no resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) may burn out (b) lights up (c) does not light
18. 18.🌈 In the resistor colour code, which number does violet stand for?
19. 19.🔋 A 3 V battery and four 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
20. 20.Which of these is a good habit? (a) log out of shared phones (b) share camera links (c) ignore update messages (d) keep factory passwords
21. 21.⏱️ How many milliseconds is a wait of 4.6 seconds?
22. 22.Which drawing is the symbol for a resistor? (a) many long-short pairs (b) a small empty box (c) a line lifted at a gap (d) a dot where wires meet
23. 23.🤖 if (light < 300 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 90 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
24. 24.📏 How many ohms (Ω) is 0.1 kΩ?
25. 25.True or false: a toggle switch flips up or down. (a) False (b) True
26. 26.🔦 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
27. 27.💡 2 identical bulbs are joined in series with a 3 V battery (ideal wires). How many volts does each bulb get? =
28. 28.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
29. 29.🌈 A resistor has the colour bands orange, grey, red. What is its value in kilo-ohms (kΩ)? =
30. 30.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to make it brighter (c) to limit the current (d) to store charge
31. 31.⏱️ How many milliseconds is a wait of 2.7 seconds?
32. 32.⏱️ repeat 3 times { buzzer ON; wait 100 ms; buzzer OFF; wait 1000 ms }
    How many milliseconds does this take in all?
33. 33.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
34. 34.🔍 A distance sensor sends a sound pulse and hears the echo 12 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
35. 35.🔌 Which metal is used for most electric wires at home? (a) rubber (b) plastic (c) glass (d) copper
36. 36.🧮 Four equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
37. 37.🔌 Is a brass key a conductor or an insulator? (a) an insulator (b) a conductor
38. 38.🧾 A 100 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
39. 39.🔺 A current of 20 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
40. 40.📶 A pin set LOW gives about … (a) 0 V (b) 9 V (c) 5 V (d) 1.5 V

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