Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 40 · 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 program says “wait 6750 ms”. How many seconds is that? =
2. 2.🗺️ In an input → process → output plan, is “a button press” the input, the process or the output? (a) output (b) process (c) input
3. 3.🧮 Three equal 30 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
4. 4.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 5 V supply. What current flows (in mA)?
5. 5.True or false: a circle with a cross is the symbol for a bulb. (a) False (b) True
6. 6.🌈 A resistor has the colour bands brown, brown, red. What is its value in kilo-ohms (kΩ)? =
7. 7.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) none (c) both of them (d) it does not matter
8. 8.💡 Why does an LED need a resistor in series? (a) to store charge (b) to make it brighter (c) to change its colour (d) to limit the current
9. 9.True or false: “compare with a limit” is the process. (a) False (b) True
10. 10.🔁 x = 2
    repeat 4 times { x = x × 2 }
    What is x at the end?
11. 11.Which job is done by the USB port? (a) brings power and code (b) keeps the voltage steady (c) connect sensors and LEDs (d) runs the program
12. 12.🔐 Is it a good or a risky habit to tap unknown app links? (a) good habit (b) risky habit
13. 13.🔺 A current of 20 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
14. 14.Which of these is safe? (a) use mains for a project (b) use a cable with cuts (c) use small battery cells (d) touch a switch when wet
15. 15.💡 What happens if an LED is put in backwards? (a) it changes colour (b) it makes a sound (c) it does not light (d) it lights brighter
16. 16.⚡ What does a doorbell mainly change electricity into? (a) movement (b) sound (c) heat (d) light
17. 17.💡 A red LED uses 2 V and should get 10 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
18. 18.🔘 A cell, a bulb and switches A and B are joined one after another in a single loop (series). A is ON and B is ON. Does the bulb glow? (a) Yes (b) No
19. 19.🔺 A current of 1 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
20. 20.What does a toggle switch do? (a) springs back when let go (b) closes when tipped over (c) closes near a magnet (d) stays where you flip it
21. 21.✏️ In a circuit diagram, which part is drawn as a line lifted at a gap? (a) switch (b) ammeter (c) diode (d) bulb
22. 22.🔁 What does a variable do in a program? (a) stores a value (b) measures light (c) joins two wires (d) blinks an LED
23. 23.📶 A pin that reads a push button is set as … (a) an output (b) a battery (c) a resistor (d) an input
24. 24.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 8 hours. How many watt-hours (Wh) are saved?
25. 25.💡 In a series circuit, how many paths does the current have? (a) two (b) one for each bulb (c) one (d) none
26. 26.🔍 Which is the odd one out? (a) a paper strip (b) a safety pin (c) a steel spoon (d) a metal paper clip
27. 27.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 7 HIGH
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) OFF (b) ON
28. 28.🤖 Does a digital thermometer usually have a microcontroller inside? (a) No (b) Yes
29. 29.What does a reed switch do? (a) works only while pressed (b) closes near a magnet (c) stays where you flip it (d) slides side to side
30. 30.🔋 What is a battery? (a) a kind of bulb (b) a switch with a lid (c) one single wire (d) two or more cells joined
31. 31.🔺 In the V-I-R triangle, how do we find I? (a) I = V + R (b) I = V × R (c) I = V ÷ R (d) I = R ÷ V
32. 32.What does a push button do? (a) stays where you flip it (b) works only while pressed (c) flips up or down (d) slides side to side
33. 33.🤖 What is a microcontroller? (a) a computer on one chip (b) a kind of bulb (c) a big desktop computer (d) a type of battery
34. 34.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
35. 35.🔦 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 plastic straw. Does the bulb glow? (a) No (b) Yes
36. 36.True or false: a slide switch flips up or down. (a) True (b) False
37. 37.⏱️ How many milliseconds is a wait of 0.2 seconds?
38. 38.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
39. 39.⏱️ How many milliseconds are in 1 second? (a) 1000 (b) 10 (c) 100 (d) 60
40. 40.🔌 Is a safety pin a conductor or an insulator? (a) a conductor (b) an insulator

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