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Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 955 · 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.💡 Why does an LED need a resistor in series? (a) to store charge (b) to limit the current (c) to make it brighter (d) to change its colour
  2. 2.⚡ A device works on 1.5 V and takes 1.5 A. What is its power (in watts)? =
  3. 3.🧭 Which part of a microcontroller board brings power and code? (a) the voltage regulator (b) the power LED (c) the pins (d) the USB port
  4. 4.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a plastic straw across the gap. Does the bulb glow? (a) Yes (b) No
  5. 5.🤖 Where does the board keep its program when the power is off? (a) the resistor (b) flash memory (c) the power LED (d) the USB cable
  6. 6.Which of these is a good habit? (a) post your live location (b) keep factory passwords (c) reuse one password (d) install software updates
  7. 7.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V × I (d) P = V ÷ I
  8. 8.🤖 if (moisture < 30) { pump ON } else { pump OFF }
    The soil moisture sensor reads 48 %. What happens?     (a) pump OFF (b) pump ON
  9. 9.🔺 A current of 0.1 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  10. 10.🔍 Which is the odd one out? (a) a smart energy meter (b) a Wi-Fi smart plug (c) a fitness band with app (d) a battery torch
  11. 11.🔦 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 dry cork. Does the bulb glow? (a) Yes (b) No
  12. 12.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the glass (c) the switch (d) the base
  13. 13.⏱️ loop forever { LED ON; wait 250 ms; LED OFF; wait 1000 ms }
    How many milliseconds does one blink (ON + OFF) take?
  14. 14.True or false: a microcontroller has a built-in keyboard. (a) True (b) False
  15. 15.⏱️ How many milliseconds is a wait of 4 seconds?
  16. 16.🔋 How many 1.2 V cells must be joined in series to give 4.8 V?
  17. 17.⚡ A cell changes stored chemical energy into which kind of energy? (a) sound energy (b) electrical energy (c) wind energy (d) nuclear energy
  18. 18.🔁 count = 3
    while (count < 13) { count = count + 5 }
    How many times does the loop run?
  19. 19.📏 In the water-pipe picture of a circuit, current is like … (a) the pipe colour (b) the water pressure (c) a narrow pipe (d) the flow of water
  20. 20.📏 Which unit measures energy used each second? (a) volt (V) (b) ohm (Ω) (c) ampere (A) (d) watt (W)
  21. 21.🔺 A current of 0.2 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  22. 22.🔁 What does a variable do in a program? (a) blinks an LED (b) measures light (c) stores a value (d) joins two wires
  23. 23.🔁 total = 0
    for i = 1 to 4 { total = total + i }
    What is total at the end?
  24. 24.🔌 Is a cotton thread a conductor or an insulator? (a) an insulator (b) a conductor
  25. 25.⚠️ Is it safe to build with an adult near? (a) safe (b) not safe
  26. 26.🔺 A 23.5 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  27. 27.🔌 Why are electric wires covered in plastic? (a) plastic is a conductor (b) plastic makes current (c) plastic is an insulator (d) to make them heavy
  28. 28.⚡ A device works on 5 V and takes 0.25 A. What is its power (in watts)? =
  29. 29.🌈 In the resistor colour code, which number does brown stand for?
  30. 30.True or false: “bulbs share the voltage” is true of a parallel circuit. (a) True (b) False
  31. 31.⚠️ Is it safe to fly kites in open fields? (a) not safe (b) safe
  32. 32.⏱️ A program says “wait 5500 ms”. How many seconds is that? =
  33. 33.🔋 What is a battery? (a) a switch with a lid (b) a kind of bulb (c) two or more cells joined (d) one single wire
  34. 34.🔍 Which is the odd one out? (a) switch off empty rooms (b) unplug idle chargers (c) use daylight to read (d) leave fridge door open
  35. 35.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 0 % (c) 5 % (d) 50 %
  36. 36.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 4300 Ω resistor? (a) yellow-orange-brown (b) yellow-orange-red (c) yellow-orange-orange (d) orange-yellow-red
  37. 37.🔍 Which is the odd one out? (a) a woollen thread (b) a brass key (c) a rubber eraser (d) a rubber band
  38. 38.⚡ Power tells us … (a) the length of a wire (b) energy used each second (c) the colour of light (d) the size of a cell
  39. 39.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = V + R (c) I = V ÷ R (d) I = R ÷ V
  40. 40.🔘 A cell and a bulb are joined to 3 side-by-side paths with one switch on each path — A, B and C (parallel). A is OFF, B is OFF and C is OFF. Does the bulb glow? (a) Yes (b) No

Answer key

  1. to limit the current
  2. 2.25
  3. the USB port
  4. No
  5. flash memory
  6. install software updates
  7. P = V × I
  8. pump OFF
  9. 1.5
  10. a battery torch
  11. No
  12. the filament
  13. 1250
  14. False
  15. 4000
  16. 4
  17. electrical energy
  18. 2
  19. the flow of water
  20. watt (W)
  21. 10
  22. stores a value
  23. 10
  24. an insulator
  25. safe
  26. 50
  27. plastic is an insulator
  28. 1.25
  29. 1
  30. False
  31. safe
  32. 5.5
  33. two or more cells joined
  34. leave fridge door open
  35. 5 %
  36. yellow-orange-red
  37. a brass key
  38. energy used each second
  39. I = V ÷ R
  40. No

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