Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 548 · 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 soil moisture reading (b) a button press (c) an LED lights up (d) a temperature reading
2. 2.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a cell is taken out (c) all wires are joined (d) the switch is OFF
3. 3.🔌 Is a rubber band a conductor or an insulator? (a) an insulator (b) a conductor
4. 4.💡 4 identical bulbs are joined in series with an 8 V battery (ideal wires). How many volts does each bulb get? =
5. 5.📶 Digital or analog: a knob turned part way? (a) digital (b) analog
6. 6.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
7. 7.🔁 count = 0
   repeat 7 times { count = count + 8 }
   What is count at the end?
8. 8.🔁 What does a variable do in a program? (a) joins two wires (b) measures light (c) blinks an LED (d) stores a value
9. 9.🔺 A 0.4 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
10. 10.🔁 repeat 3 times { repeat 4 times { beep } }
    How many beeps are there?
11. 11.Which of these is an input? (a) an LED (b) a water pump (c) a motion sensor (d) a servo motor
12. 12.🌈 A resistor has the colour bands green, green, black. What is its value (in ohms)?
13. 13.🔐 Who should decide which smart devices go in a child’s room? (a) a parent or guardian (b) an online stranger (c) nobody at all (d) the app’s adverts
14. 14.⚡ What does an electric iron mainly change electricity into? (a) light (b) heat (c) sound (d) movement
15. 15.Which of these is the process? (a) an LED lights up (b) a button press (c) a buzzer beeps (d) check if temp > 30
16. 16.💡 An LED is joined to a 5 V battery through a 330 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
17. 17.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 1 hour. How many watt-hours (Wh) are saved?
18. 18.💡 Why does an LED need a resistor in series? (a) to store charge (b) to make it brighter (c) to limit the current (d) to change its colour
19. 19.📏 How many watts (W) is 4.5 kW?
20. 20.🧩 Which component has coloured bands? (a) transistor (b) fuse (c) resistor (d) capacitor
21. 21.💡 2 identical bulbs are joined in series with a battery and a closed switch on the main wire. All the bulbs are in place. How many bulbs glow?
22. 22.🔍 Which is the odd one out? (a) a battery torch (b) a plain table fan (c) a pencil sharpener (d) a smart energy meter
23. 23.⏱️ loop forever { LED ON; wait 450 ms; LED OFF; wait 850 ms }
    How many milliseconds does one blink (ON + OFF) take?
24. 24.True or false: energy used each second is measured in watts (W). (a) True (b) False
25. 25.⚡ Which formula gives electric power? (a) P = V × I (b) P = I ÷ V (c) P = V + I (d) P = V ÷ I
26. 26.🗺️ Before building a project, what should you write down first? (a) inputs and outputs (b) the final price (c) nothing at all (d) the box colour
27. 27.💡 What happens if an LED is put in backwards? (a) it does not light (b) it lights brighter (c) it changes colour (d) it makes a sound
28. 28.🔗 Series or parallel circuit: “bulbs share the voltage”? (a) parallel (b) series
29. 29.Which job is done by the voltage regulator? (a) runs the program (b) connect sensors and LEDs (c) shows the board is on (d) keeps the voltage steady
30. 30.Which of these mainly gives out light? (a) an LED lamp (b) a school bell (c) a water heater (d) a doorbell
31. 31.⚡ A bicycle dynamo changes which kind of energy into electricity? (a) sound energy (b) chemical energy (c) movement energy (d) light energy
32. 32.True or false: “count button presses” is the process. (a) False (b) True
33. 33.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
34. 34.🔍 An object is 170 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
35. 35.🔺 A 2.5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
36. 36.💡 2 identical bulbs are joined in parallel across a 9 V battery (ideal wires). How many volts does each bulb get? =
37. 37.🔺 A current of 3 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
38. 38.⏱️ How many milliseconds is a wait of 2.8 seconds?
39. 39.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 4 V supply. What current flows (in mA)?
40. 40.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True

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