Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 58 · 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 an old-style bulb, which thin wire glows when current flows? (a) the base (b) the filament (c) the switch (d) the glass
2. 2.🔍 For a microcontroller, is a sensor an input or an output? (a) a fuse (b) a power source (c) an output (d) an input
3. 3.Which job needs a servo motor? (a) show a status light (b) beep an alarm (c) open a gate to 90° (d) show the temperature
4. 4.🔋 A 3 V battery and one 1.5 V cell are joined in series, all facing the same way. What is the total voltage (in volts)? =
5. 5.🤖 if (moisture < 40) { pump ON } else { pump OFF }
   The soil moisture sensor reads 52 %. What happens? (a) pump OFF (b) pump ON
6. 6.💡 In a series circuit, how many paths does the current have? (a) two (b) one for each bulb (c) none (d) one
7. 7.🔁 What does a variable do in a program? (a) stores a value (b) measures light (c) joins two wires (d) blinks an LED
8. 8.🔺 A 3 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
9. 9.⏱️ loop forever { LED ON; wait 50 ms; LED OFF; wait 150 ms }
   How many times does the LED blink in 2 seconds?
10. 10.🔍 Which is the odd one out? (a) leave fridge door open (b) use daylight to read (c) leave the TV on standby (d) iron one shirt at a time
11. 11.💡 A blue LED uses 3 V and should get 20 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
12. 12.🔍 Which is the odd one out? (a) an electric kettle (b) an LED lamp (c) a tube light (d) a torch
13. 13.True or false: to close a window in rain, use a sound sensor. (a) False (b) True
14. 14.🔢 To plan an electronics project, which is the LAST step? (a) pick a problem to solve (b) list inputs and outputs (c) draw the circuit diagram (d) test it and fix it
15. 15.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a series circuit (c) an open circuit (d) a full circuit
16. 16.True or false: a fuse blows if current is high. (a) False (b) True
17. 17.💡 2 identical bulbs are joined in series with an 8 V battery (ideal wires). How many volts does each bulb get? =
18. 18.Which of these is safe? (a) open a phone charger (b) poke things in a socket (c) keep drinks far away (d) climb an electric pole
19. 19.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V ÷ R (c) I = V + R (d) I = V × R
20. 20.⏱️ What does “wait 500 ms” do? (a) blinks 500 times (b) waits 500 seconds (c) pauses for half a second (d) turns the LED off
21. 21.🤖 if (temperature > 28) { fan ON } else { fan OFF }
    The temperature sensor reads 36 °C. What happens? (a) fan ON (b) fan OFF
22. 22.True or false: a straight line is the symbol for a wire. (a) True (b) False
23. 23.Which job needs an LED? (a) show a status light (b) open a gate to 90° (c) beep an alarm (d) show the temperature
24. 24.💡 A red LED uses 2 V and should get 25 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
25. 25.🔁 repeat 4 times { repeat 2 times { beep } }
    How many beeps are there?
26. 26.🔌 Is aluminium foil a conductor or an insulator? (a) an insulator (b) a conductor
27. 27.🔍 Which is the odd one out? (a) an LED (b) a turning knob (c) a servo motor (d) a speaker
28. 28.🔺 A current of 0.25 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
29. 29.🔢 To run one loop of a plant-watering program, which comes first: “wait a few seconds” or “read the soil sensor”? (a) wait a few seconds (b) read the soil sensor
30. 30.🔋 Identical cells side by side (in parallel) give … (a) half the voltage (b) double the voltage (c) no voltage (d) the same voltage
31. 31.🤖 if (light < 200) { lamp ON } else { lamp OFF }
    The light sensor reads 60. What happens? (a) lamp OFF (b) lamp ON
32. 32.🔺 A current of 40 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
33. 33.True or false: “one out, the rest glow” is true of a series circuit. (a) False (b) True
34. 34.True or false: to log out of shared phones is a good habit. (a) False (b) True
35. 35.🧮 Five equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
36. 36.📏 How many watts (W) is 0.3 kW?
37. 37.🔋 How many volts does one ordinary torch cell give? (a) 230 V (b) 1.5 V (c) 0.5 V (d) 15 V
38. 38.🔢 To run one loop of a plant-watering program, what comes right after “read the soil sensor”? (a) compare with the limit (b) switch the pump on/off (c) wait a few seconds
39. 39.🤖 if (moisture < 30) { pump ON } else { pump OFF }
    The soil moisture sensor reads 16 %. What happens? (a) pump OFF (b) pump ON
40. 40.⚠️ Someone is getting a shock and is still touching a wire. What should you do? (a) pull them by the hand (b) wait and watch (c) pour water on them (d) shout for an adult

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