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Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 925 · 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.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they get dimmer (b) they explode (c) they keep glowing (d) they all go out
  2. 2.True or false: to set the AC to 24 °C saves electricity. (a) False (b) True
  3. 3.🔺 A 15 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  4. 4.⚠️ A cell gets hot when its + and − ends are joined by a bare wire. What is this called? (a) an open circuit (b) a parallel circuit (c) a short circuit (d) a safe circuit
  5. 5.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  6. 6.🔢 To get a sensor reading onto a phone, which comes first: “it is sent by Wi-Fi” or “the app shows it”? (a) the app shows it (b) it is sent by Wi-Fi
  7. 7.🔋 A 9 V battery and three 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
  8. 8.🔋 A 6 V battery and one 1.5 V cell are joined in series, all facing the same way. What is the total voltage (in volts)? =
  9. 9.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 25 % (c) 5 % (d) 50 %
  10. 10.True or false: an LED lamp mainly gives out heat. (a) True (b) False
  11. 11.Which job needs a light sensor? (a) keep an incubator warm (b) open blinds at sunrise (c) switch on with a clap (d) water a dry plant
  12. 12.💡 3 identical bulbs are joined in series with a battery and a closed switch on the main wire. All the bulbs are in place. How many bulbs glow?
  13. 13.⏱️ repeat 2 times { buzzer ON; wait 800 ms; buzzer OFF; wait 500 ms }
    How many milliseconds does this take in all?
  14. 14.Which job is done by the pins? (a) connect sensors and LEDs (b) brings power and code (c) runs the program (d) restarts the program
  15. 15.🔋 5 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
  16. 16.🔗 Series or parallel circuit: “used in house wiring”? (a) series (b) parallel
  17. 17.✏️ In a cell symbol, which line is the + terminal? (a) neither line (b) the shorter line (c) both lines (d) the longer line
  18. 18.💡 Does it save or waste electricity to use daylight to read? (a) saves electricity (b) wastes electricity
  19. 19.📏 How many ohms (Ω) is 2.2 kΩ?
  20. 20.True or false: to set up with a parent is a risky habit. (a) False (b) True
  21. 21.⏱️ How many milliseconds is a wait of 1.2 seconds?
  22. 22.💡 3 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 1 is taken out of its holder. Does bulb 2 glow? (a) No (b) Yes
  23. 23.Which of these is a good habit? (a) share the Wi-Fi key (b) set up with a parent (c) ignore update messages (d) accept every permission
  24. 24.⏱️ loop forever { LED ON; wait 200 ms; LED OFF; wait 200 ms }
    How many times does the LED blink in 4 seconds?
  25. 25.🌈 A resistor has the colour bands red, brown, red. What is its value in kilo-ohms (kΩ)? =
  26. 26.💡 A red LED uses 2 V and should get 20 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
  27. 27.True or false: “count button presses” is the process. (a) False (b) True
  28. 28.🔌 Why are electric wires covered in plastic? (a) to make them heavy (b) plastic is an insulator (c) plastic is a conductor (d) plastic makes current
  29. 29.🔍 Which sensor would you use to open blinds at sunrise? (a) a light sensor (b) a motion sensor (c) a distance sensor (d) a soil moisture sensor
  30. 30.✏️ In a circuit diagram, wires are usually drawn as … (a) little stars (b) wavy lines (c) dotted circles (d) straight lines
  31. 31.🔺 A current of 1.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  32. 32.🔁 total = 0
    for i = 1 to 12 { total = total + i }
    What is total at the end?
  33. 33.True or false: “a knob turned part way” is a digital signal. (a) False (b) True
  34. 34.Which of these has no microcontroller inside? (a) a washing machine (b) a toy robot (c) a digital thermometer (d) a candle
  35. 35.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
  36. 36.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 8 LOW
    set pin 8 HIGH
    Is the LED ON or OFF at the end?     (a) ON (b) OFF
  37. 37.Which job needs a temperature sensor? (a) stop a robot near walls (b) warn of a gas leak (c) spot someone walking in (d) start a fan when hot
  38. 38.⚡ Which formula gives electric power? (a) P = V × I (b) P = V + I (c) P = V ÷ I (d) P = I ÷ V
  39. 39.🔋 A 12 V battery and three 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
  40. 40.⚡ A device works on 12 V and takes 0.1 A. What is its power (in watts)? =

Answer key

  1. they keep glowing
  2. True
  3. 1.5
  4. a short circuit
  5. open
  6. it is sent by Wi-Fi
  7. 13.5
  8. 7.5
  9. 5 %
  10. False
  11. open blinds at sunrise
  12. 3
  13. 2600
  14. connect sensors and LEDs
  15. 4.5
  16. parallel
  17. the longer line
  18. saves electricity
  19. 2200
  20. False
  21. 1200
  22. No
  23. set up with a parent
  24. 10
  25. 2.1
  26. 350
  27. True
  28. plastic is an insulator
  29. a light sensor
  30. straight lines
  31. 7.5
  32. 78
  33. False
  34. a candle
  35. 1840
  36. OFF
  37. start a fan when hot
  38. P = V × I
  39. 16.5
  40. 1.2

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