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Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 258 · 40 questions
TalentJR

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.

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  1. 1.True or false: to measure classroom noise, use a temperature sensor. (a) False (b) True
  2. 2.🔗 Series or parallel circuit: “each gets the full volts”? (a) parallel (b) series
  3. 3.🔁 total = 0
    for i = 1 to 12 { total = total + i }
    What is total at the end?
  4. 4.Which of these saves electricity? (a) use LED lamps (b) leave fridge door open (c) use old filament bulbs (d) run fans in empty rooms
  5. 5.📏 How many kilo-ohms (kΩ) is 2300 Ω? =
  6. 6.⚡ What does a water heater mainly change electricity into? (a) sound (b) light (c) movement (d) heat
  7. 7.🔺 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
  8. 8.🧮 A 470 Ω resistor is joined in series with two equal 470 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  9. 9.True or false: to change default passwords is a good habit. (a) False (b) True
  10. 10.True or false: to post your live location is a good habit. (a) False (b) True
  11. 11.🔺 A current of 2.5 A flows when 50 V is joined across a resistor. What is its resistance (in ohms)?
  12. 12.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
  13. 13.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in series (b) by Wi-Fi (c) in parallel (d) not joined
  14. 14.🧮 Resistors of 10 Ω, 10 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
  15. 15.Which of these uses electricity? (a) a solar panel (b) a bicycle dynamo (c) a generator (d) a water pump
  16. 16.What does a push button do? (a) works only while pressed (b) closes near a magnet (c) closes when tipped over (d) stays where you flip it
  17. 17.💡 What happens if an LED is put in backwards? (a) it does not light (b) it changes colour (c) it makes a sound (d) it lights brighter
  18. 18.🔺 A 6 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  19. 19.⏱️ How many milliseconds is a wait of 3.6 seconds?
  20. 20.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a metal paper clip across the gap. Does the bulb glow? (a) No (b) Yes
  21. 21.True or false: a glass marble is an insulator. (a) True (b) False
  22. 22.🔋 How many 2 V cells must be joined in series to give 6 V?
  23. 23.⚠️ Is it safe to touch a switch when wet? (a) not safe (b) safe
  24. 24.🧩 A capacitor in a circuit can … (a) measure heat (b) store charge briefly (c) make light (d) spin a wheel
  25. 25.🔺 A 1 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  26. 26.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the output (b) the input (c) the battery (d) the process
  27. 27.🔁 What does a variable do in a program? (a) joins two wires (b) measures light (c) stores a value (d) blinks an LED
  28. 28.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 25 Ω resistor? (a) red-green-black (b) red-green-brown (c) orange-green-black (d) green-red-black
  29. 29.🔺 A 4 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  30. 30.🔘 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) No (b) Yes
  31. 31.🔁 x = 3
    repeat 2 times { x = x × 2 }
    What is x at the end?
  32. 32.True or false: a straight line is the symbol for a switch. (a) True (b) False
  33. 33.🧾 A 250 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
  34. 34.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
  35. 35.🔐 A smart speaker is always listening for its wake word. What is a sensible habit? (a) mute it when not in use (b) put it in the bathroom (c) tell it your passwords (d) let strangers use it
  36. 36.✏️ In a circuit diagram, which part is drawn as triangle, bar and arrows? (a) battery (b) switch (c) LED (d) junction
  37. 37.🔍 Which sensor would you use to make a parking alarm? (a) a soil moisture sensor (b) a sound sensor (c) a rain sensor (d) a distance sensor
  38. 38.🔘 A cell, a bulb and switches A, B, C and D are joined one after another in a single loop (series). A is ON, B is ON, C is OFF and D is OFF. Does the bulb glow? (a) Yes (b) No
  39. 39.🧮 Five equal 250 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  40. 40.🔺 A current of 0.1 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =

Answer key

  1. False
  2. parallel
  3. 78
  4. use LED lamps
  5. 2.3
  6. heat
  7. I = V ÷ R
  8. 705
  9. True
  10. False
  11. 20
  12. No
  13. in series
  14. 70
  15. a water pump
  16. works only while pressed
  17. it does not light
  18. 40
  19. 3600
  20. Yes
  21. True
  22. 3
  23. not safe
  24. store charge briefly
  25. 0.1
  26. the process
  27. stores a value
  28. red-green-black
  29. 40
  30. Yes
  31. 12
  32. False
  33. 1.25
  34. 238
  35. mute it when not in use
  36. LED
  37. a distance sensor
  38. No
  39. 50
  40. 2

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