Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 199 · 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) an electric kettle (b) a loudspeaker (c) a doorbell (d) a buzzer
2. 2.⚡ A cell changes stored chemical energy into which kind of energy? (a) wind energy (b) nuclear energy (c) sound energy (d) electrical energy
3. 3.🤖 Which is a safe power source for a beginner microcontroller board? (a) a wall socket directly (b) bare mains wires (c) USB or a 9 V battery (d) a 230 V cable
4. 4.True or false: a push button closes when tipped over. (a) False (b) True
5. 5.Which of these usually has a microcontroller inside? (a) a candle (b) a digital thermometer (c) a bicycle bell (d) a spinning top
6. 6.🤖 if (temperature > 30) { fan ON } else { fan OFF }
   The temperature sensor reads 32 °C. What happens? (a) fan ON (b) fan OFF
7. 7.🔘 A cell and a bulb are joined to 2 side-by-side paths with one switch on each path — A and B (parallel). A is OFF and B is ON. Does the bulb glow? (a) Yes (b) No
8. 8.True or false: to unplug idle chargers wastes electricity. (a) False (b) True
9. 9.🧮 Three equal 300 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
10. 10.🔺 A current of 20 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
11. 11.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the filament (d) the base
12. 12.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 7 LOW
    set pin 7 HIGH
    set pin 8 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF
13. 13.True or false: on an LED, the round-side leg is the anode (+). (a) False (b) True
14. 14.🔁 total = 0
    for i = 1 to 6 { total = total + i }
    What is total at the end?
15. 15.What does a potentiometer do? (a) senses how bright it is (b) is a resistance knob (c) glows using little power (d) limits the current
16. 16.Which drawing is the symbol for a motor? (a) a circle with M inside (b) a long and a short line (c) triangle, bar and arrows (d) many long-short pairs
17. 17.True or false: current is measured in watts (W). (a) True (b) False
18. 18.Which of these is safe? (a) use small battery cells (b) fly a kite near wires (c) touch a fallen wire (d) use mains for a project
19. 19.True or false: a circle with M inside is the symbol for a motor. (a) False (b) True
20. 20.True or false: “a motion sensor signal” is the output. (a) True (b) False
21. 21.🗺️ In an input → process → output plan, is “count button presses” the input, the process or the output? (a) input (b) output (c) process
22. 22.Which of these usually has a microcontroller inside? (a) a bicycle bell (b) a wind-up toy (c) a candle (d) a toy robot
23. 23.🌈 A resistor has the colour bands yellow, blue, black. What is its value (in ohms)?
24. 24.✏️ Why do engineers draw circuits with symbols? (a) to make it colourful (b) quick and clear for all (c) to hide the circuit (d) symbols are heavier
25. 25.🔺 A current of 10 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
26. 26.Which job is done by the voltage regulator? (a) keeps the voltage steady (b) restarts the program (c) runs the program (d) connect sensors and LEDs
27. 27.Which of these is measured in ohms (Ω)? (a) power (b) how much a part resists (c) the push of a cell (d) voltage
28. 28.🔘 Which kind of switch springs back when let go? (a) a push button (b) a reed switch (c) a tilt switch (d) a toggle switch
29. 29.📶 On a 5 V board, a pin set HIGH gives about … (a) 50 V (b) 0 V (c) 5 V (d) 230 V
30. 30.🔌 Is a woollen thread a conductor or an insulator? (a) an insulator (b) a conductor
31. 31.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
32. 32.Which of these means the circuit is open? (a) all wires are joined (b) a wire is cut (c) the switch is ON (d) the loop is complete
33. 33.True or false: an LED beeps for an alarm. (a) False (b) True
34. 34.Which of these usually has a microcontroller inside? (a) a spinning top (b) a plain wall switch (c) a microwave oven (d) a hand pump
35. 35.True or false: a microcontroller runs many apps at once. (a) False (b) True
36. 36.🔌 A gap of dry air between two wires acts as … (a) an insulator (b) a cell (c) a switch that is ON (d) a conductor
37. 37.💡 An LED is joined to a 5 V battery through a 1000 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) lights up (b) does not light (c) may burn out
38. 38.🔍 Which is the odd one out? (a) use a cable with cuts (b) fly a kite near wires (c) use mains for a project (d) keep drinks far away
39. 39.Which of these is true of a parallel circuit? (a) a break stops every bulb (b) bulbs share the voltage (c) a single current path (d) many paths for current
40. 40.⚡ A 2.4 W device works on 24 V. What current does it take (in amperes)? =

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