Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 544 · 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.🌐 Is a wind-up clock an IoT device? (a) not an IoT device (b) an IoT device
2. 2.🧮 Two resistors in parallel give a total that is … (a) their sum (b) always zero (c) less than either one (d) more than either one
3. 3.🔍 An object is 323 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
4. 4.🧮 Resistors of 20 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
5. 5.🌐 In an IoT system, which part measures the real world? (a) actuator (b) phone app (c) microcontroller (d) sensor
6. 6.🌐 What does IoT stand for? (a) Input of Tools (b) Internet of Things (c) Internet of Talk (d) Inside of Toys
7. 7.True or false: to poke things in a socket is safe. (a) True (b) False
8. 8.What does a reed switch do? (a) closes when tipped over (b) slides side to side (c) flips up or down (d) closes near a magnet
9. 9.🔺 A current of 50 mA flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
10. 10.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. A gap in one wire is bridged by a cotton thread. Does the bulb glow? (a) No (b) Yes
11. 11.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V + I (c) P = I ÷ V (d) P = V × I
12. 12.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) True (b) False
13. 13.🧩 Which component has coloured bands? (a) transistor (b) resistor (c) LDR (d) thermistor
14. 14.🔺 A 15 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
15. 15.🤖 Microcontroller or laptop: which one uses very little power? (a) laptop (b) microcontroller
16. 16.🌈 In the resistor colour code, which number does red stand for?
17. 17.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
18. 18.🧩 A capacitor in a circuit can … (a) spin a wheel (b) measure heat (c) make light (d) store charge briefly
19. 19.🧭 Which part of a microcontroller board runs the program? (a) the main chip (b) the voltage regulator (c) the pins (d) the power LED
20. 20.🤖 if (light < 300 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 110 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
21. 21.Which job needs a soil moisture sensor? (a) make a parking alarm (b) close a window in rain (c) water a dry plant (d) start a fan when hot
22. 22.Which job needs a rain sensor? (a) start a fan when hot (b) close a window in rain (c) switch on with a clap (d) water a dry plant
23. 23.What does a buzzer do? (a) boosts a small signal (b) smooths a wobbly supply (c) blows if current is high (d) beeps for an alarm
24. 24.🔘 When a switch is ON, the circuit is … (a) cut (b) open (c) closed (d) broken
25. 25.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
26. 26.True or false: a loudspeaker mainly makes sound. (a) True (b) False
27. 27.Which of these is true of a series circuit? (a) a single current path (b) own switch for each bulb (c) each gets the full volts (d) one out, the rest glow
28. 28.🧾 A 2000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
29. 29.🌈 A resistor has the colour bands grey, white, brown. What is its value (in ohms)?
30. 30.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. A gap in one wire is bridged by a metal paper clip. Does the bulb glow? (a) Yes (b) No
31. 31.True or false: a toggle switch flips up or down. (a) False (b) True
32. 32.What does the phone app do? (a) measures the real world (b) reads values, decides (c) acts on a command (d) shows data to you
33. 33.Which drawing is the symbol for a junction? (a) two or more cell symbols (b) a small empty box (c) two equal parallel lines (d) a dot where wires meet
34. 34.🔍 Which is the odd one out? (a) a smart energy meter (b) a Wi-Fi weather station (c) an app-controlled bulb (d) a battery torch
35. 35.True or false: to stop a robot near walls, use a distance sensor. (a) False (b) True
36. 36.⚠️ Someone is getting a shock and is still touching a wire. What should you do? (a) wait and watch (b) pull them by the hand (c) pour water on them (d) shout for an adult
37. 37.🔌 Is a push button an input or an output for a microcontroller? (a) input (b) output
38. 38.Which of these is an output? (a) a turning knob (b) a motor (c) a push button (d) a motion sensor
39. 39.🔺 A current of 40 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
40. 40.💡 2 identical bulbs are joined in series with a 3 V battery (ideal wires). How many volts does each bulb get? =

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