Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 904 · 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 light sensor (b) an LED (c) a sound sensor (d) a push button
2. 2.True or false: to run fans in empty rooms saves electricity. (a) True (b) False
3. 3.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 6 V supply. What current flows (in mA)?
4. 4.Which job needs a motor? (a) show the temperature (b) show a status light (c) spin a robot’s wheels (d) move water to plants
5. 5.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) gets smaller (c) stays the same (d) gets bigger
6. 6.True or false: a small empty box is the symbol for a capacitor. (a) True (b) False
7. 7.🔌 A gap of dry air between two wires acts as … (a) a switch that is ON (b) a conductor (c) a cell (d) an insulator
8. 8.🤖 if (light < 400 OR motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 610 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
9. 9.📏 Which unit measures how much a part resists? (a) ohm (Ω) (b) watt (W) (c) volt (V) (d) ampere (A)
10. 10.What does the phone app do? (a) shows data to you (b) carries the data (c) measures the real world (d) acts on a command
11. 11.💡 What does LED stand for? (a) light energy dial (b) low energy device (c) large electric dial (d) light-emitting diode
12. 12.Which of these is safe? (a) use mains for a project (b) use small battery cells (c) open a phone charger (d) throw cells in a fire
13. 13.True or false: on a cell, “the shorter symbol line” means the − (negative) end. (a) True (b) False
14. 14.🤖 Microcontroller or laptop: which one uses very little power? (a) laptop (b) microcontroller
15. 15.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a rubber eraser. Does the bulb glow? (a) No (b) Yes
16. 16.True or false: “a single current path” is true of a series circuit. (a) False (b) True
17. 17.🔺 A current of 20 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
18. 18.🤖 if (temperature > 32) { show “Hot” } else if (temperature > 19) { show “Warm” } else { show “Cool” }
    The temperature is 26 °C. What is shown? (a) Warm (b) Cool (c) Hot
19. 19.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
20. 20.💡 A blue LED uses 3 V and should get 25 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
21. 21.🔘 Two switches are in series. When does the bulb glow? (a) when either is ON (b) when both are OFF (c) never (d) when both are ON
22. 22.🔋 3 identical 1.5 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
23. 23.🔁 What does “count = count + 1” do? (a) adds 1 to count (b) takes 1 away (c) sets count to 1 (d) prints 1
24. 24.⚡ What does a table fan mainly change electricity into? (a) sound (b) light (c) movement (d) heat
25. 25.Which job is done by the voltage regulator? (a) connect sensors and LEDs (b) keeps the voltage steady (c) shows the board is on (d) runs the program
26. 26.🔐 Why install updates on IoT devices? (a) they fix security holes (b) they make it heavier (c) they change the colour (d) they delete the Wi-Fi
27. 27.True or false: a dot where wires meet is the symbol for a junction. (a) False (b) True
28. 28.🔋 3 identical 2 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
29. 29.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 HIGH
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) OFF (b) ON
30. 30.Which of these mainly gives out heat? (a) a street light (b) an electric kettle (c) an electric toy car (d) a doorbell
31. 31.💡 4 identical bulbs are joined in series with a battery and a closed switch on the main wire. All the bulbs are in place. Does bulb 3 glow? (a) Yes (b) No
32. 32.🔍 Which is the odd one out? (a) a Wi-Fi doorbell camera (b) a Wi-Fi smart plug (c) a Wi-Fi weather station (d) a plain wall switch
33. 33.🔐 Privacy for a smart device means controlling … (a) its colour (b) who can see your data (c) how loud it beeps (d) its battery size
34. 34.Which of these means the circuit is open? (a) the switch is ON (b) the bulb is unscrewed (c) the loop is complete (d) all wires are joined
35. 35.⏱️ loop forever { LED ON; wait 750 ms; LED OFF; wait 200 ms }
    How many milliseconds does one blink (ON + OFF) take?
36. 36.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
37. 37.🌈 In the resistor colour code, which number does black stand for?
38. 38.💡 3 identical bulbs are joined in parallel across a 9 V battery (ideal wires). How many volts does each bulb get? =
39. 39.True or false: a toggle switch flips up or down. (a) True (b) False
40. 40.True or false: to stop if a part gets hot is safe. (a) True (b) False

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