Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 777 · 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.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = R ÷ V (c) I = V × R (d) I = V + R
2. 2.⏱️ loop forever { LED ON; wait 650 ms; LED OFF; wait 800 ms }
   How many milliseconds does one blink (ON + OFF) take?
3. 3.🧮 A 1.4 V battery is joined to 6 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
4. 4.🔘 Switch A is on the main wire next to the cell and the bulb; then the wire splits into two side-by-side paths, one with switch B and one with switch C. A is OFF, B is ON and C is ON. Does the bulb glow? (a) No (b) Yes
5. 5.Which of these is an output? (a) a sound sensor (b) a light sensor (c) an LED (d) a turning knob
6. 6.💡 4 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
7. 7.⚙️ What is an actuator? (a) an output that acts (b) a battery (c) a sensor (d) a program
8. 8.✏️ In a circuit diagram, which part is drawn as one tall, one short bar? (a) cell (b) resistor (c) battery (d) switch
9. 9.Which job is done by the pins? (a) connect sensors and LEDs (b) brings power and code (c) keeps the voltage steady (d) shows the board is on
10. 10.True or false: to close the fridge quickly wastes electricity. (a) False (b) True
11. 11.🤖 Microcontroller or laptop: which one uses very little power? (a) laptop (b) microcontroller
12. 12.🔺 A 6 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
13. 13.What does the sensor do? (a) stores data online (b) measures the real world (c) carries the data (d) acts on a command
14. 14.🧩 Which part changes electrical energy into movement? (a) a resistor (b) a motor (c) a fuse (d) an LED
15. 15.🧩 Which component smooths a wobbly supply? (a) buzzer (b) capacitor (c) resistor (d) thermistor
16. 16.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
17. 17.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
18. 18.🤖 if (light < 400 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 130 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON
19. 19.💡 An LED is joined to a 6 V battery through a 220 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) lights up (c) may burn out
20. 20.Which job is done by the USB port? (a) shows the board is on (b) connect sensors and LEDs (c) restarts the program (d) brings power and code
21. 21.📏 How many watts (W) is 3.9 kW?
22. 22.True or false: “a single current path” is true of a series circuit. (a) False (b) True
23. 23.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) use LED lamps (c) run fans in empty rooms (d) use daylight to read
24. 24.📶 On a 5 V board, a pin set HIGH gives about … (a) 5 V (b) 0 V (c) 230 V (d) 50 V
25. 25.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) by Wi-Fi (b) in parallel (c) in series (d) not joined
26. 26.🔍 Which is the odd one out? (a) a table fan (b) a night lamp (c) a traffic signal (d) a tube light
27. 27.🔐 Who should decide which smart devices go in a child’s room? (a) an online stranger (b) the app’s adverts (c) nobody at all (d) a parent or guardian
28. 28.🔘 Switch A is on the main wire next to the cell and the bulb; then the wire splits into two side-by-side paths, one with switch B and one with switch C. A is OFF, B is OFF and C is ON. Does the bulb glow? (a) No (b) Yes
29. 29.🌈 A resistor has the colour bands yellow, yellow, red. What is its value in kilo-ohms (kΩ)? =
30. 30.🌈 A resistor has the colour bands violet, black, red. What is its value in kilo-ohms (kΩ)? =
31. 31.🔋 How many 1.2 V cells must be joined in series to give 3.6 V?
32. 32.True or false: the flow of charge is measured in volts (V). (a) True (b) False
33. 33.⚡ What do we call a flow of electric charge through a wire? (a) sound (b) electric current (c) friction (d) a magnet
34. 34.True or false: a thermistor smooths a wobbly supply. (a) True (b) False
35. 35.🌈 A resistor has the colour bands green, red, yellow. What is its value in kilo-ohms (kΩ)? =
36. 36.🔺 A current of 10 mA flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
37. 37.🔢 To run one loop of a plant-watering program, what comes right after “compare with the limit”? (a) switch the pump on/off (b) read the soil sensor (c) wait a few seconds
38. 38.🤖 Microcontroller or laptop: which one has a built-in keyboard? (a) laptop (b) microcontroller
39. 39.💡 A battery lights 4 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) dimmer (b) the same (c) brighter
40. 40.Which of these saves electricity? (a) switch off empty rooms (b) leave the TV on standby (c) use old filament bulbs (d) run fans in empty rooms

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