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Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 252 · 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 run fans in empty rooms saves electricity. (a) False (b) True
  2. 2.💡 An LED is joined to a 5 V battery through a 470 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) may burn out (b) does not light (c) lights up
  3. 3.🔘 Switch A is on the main wire next to the cell and the bulb; then the wire splits into two side-by-side paths, one with switch B and one with switch C. A is OFF, B is ON and C is OFF. Does the bulb glow? (a) No (b) Yes
  4. 4.What does a tilt switch do? (a) flips up or down (b) closes when tipped over (c) stays where you flip it (d) slides side to side
  5. 5.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
  6. 6.Which job needs a soil moisture sensor? (a) switch on lamps at dusk (b) open blinds at sunrise (c) keep an incubator warm (d) water a dry plant
  7. 7.🔘 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 ON. Does the bulb glow? (a) Yes (b) No
  8. 8.Which of these mainly makes movement? (a) an electric iron (b) a room heater (c) a torch (d) an exhaust fan
  9. 9.⚡ A device works on 3 V and takes 3 A. What is its power (in watts)? =
  10. 10.True or false: a tube light mainly makes sound. (a) False (b) True
  11. 11.🔍 Which is the odd one out? (a) a loudspeaker (b) a siren (c) a buzzer (d) a ceiling fan
  12. 12.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 2.5 V supply. What current flows (in mA)?
  13. 13.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) none (c) both of them (d) only one
  14. 14.⚙️ Which actuator would you use to open a gate to 90°? (a) a servo motor (b) an LED (c) a buzzer (d) a display
  15. 15.🤖 Does a TV remote usually have a microcontroller inside? (a) Yes (b) No
  16. 16.🤖 “if (A AND B)” is true when … (a) both are false (b) both A and B are true (c) only A is true (d) only B is true
  17. 17.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 6.5 V supply. What current flows (in mA)?
  18. 18.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the process (b) the input (c) the battery (d) the output
  19. 19.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) True (b) False
  20. 20.🔋 How many 1.2 V cells must be joined in series to give 3.6 V?
  21. 21.🌐 A soil sensor sends a reading to an app every 30 minutes. How many readings arrive in 3 hours?
  22. 22.🔌 Is a dry cork a conductor or an insulator? (a) an insulator (b) a conductor
  23. 23.⚡ Power tells us … (a) energy used each second (b) the size of a cell (c) the length of a wire (d) the colour of light
  24. 24.🔍 Which is the odd one out? (a) a smart energy meter (b) a paper calendar (c) a plain table fan (d) a pencil sharpener
  25. 25.💡 5 identical bulbs are joined in parallel across a 4.5 V battery (ideal wires). How many volts does each bulb get? =
  26. 26.⚠️ Which power source should children use for electronics projects? (a) an inverter socket (b) a wall socket (c) a small battery pack (d) a mains extension board
  27. 27.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I + R (c) V = R ÷ I (d) V = I × R
  28. 28.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V × I (d) P = V + I
  29. 29.🔋 A 3 V battery and two 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
  30. 30.Which of these mainly makes sound? (a) a table fan (b) a torch (c) an electric drill (d) a siren
  31. 31.Which of these is measured in volts (V)? (a) voltage (b) resistance (c) power (d) the flow of charge
  32. 32.True or false: a smart watch has no microcontroller inside. (a) True (b) False
  33. 33.🔋 Does a generator give electricity or use electricity? (a) gives electricity (b) uses electricity
  34. 34.True or false: “a break stops every bulb” is true of a series circuit. (a) False (b) True
  35. 35.🔺 A 50 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  36. 36.🔁 count = 1
    while (count < 17) { count = count + 4 }
    How many times does the loop run?
  37. 37.⚠️ Is it safe to throw cells in a fire? (a) not safe (b) safe
  38. 38.📏 Which unit measures energy used each second? (a) ohm (Ω) (b) volt (V) (c) ampere (A) (d) watt (W)
  39. 39.🔺 A current of 0.1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.📶 Digital or analog: HIGH or LOW only? (a) digital (b) analog

Answer key

  1. False
  2. does not light
  3. No
  4. closes when tipped over
  5. saves electricity
  6. water a dry plant
  7. Yes
  8. an exhaust fan
  9. 9
  10. False
  11. a ceiling fan
  12. 5
  13. both of them
  14. a servo motor
  15. Yes
  16. both A and B are true
  17. 15
  18. the process
  19. True
  20. 3
  21. 6
  22. an insulator
  23. energy used each second
  24. a smart energy meter
  25. 4.5
  26. a small battery pack
  27. V = I × R
  28. P = V × I
  29. 6
  30. a siren
  31. voltage
  32. False
  33. gives electricity
  34. True
  35. 2.5
  36. 4
  37. not safe
  38. watt (W)
  39. 0.4
  40. digital

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