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Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 374 · 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: “many paths for current” is true of a parallel circuit. (a) True (b) False
  2. 2.🧩 Which component makes a beeping sound? (a) fuse (b) capacitor (c) buzzer (d) diode
  3. 3.💡 An LED is joined to a 9 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) lights up (b) may burn out (c) does not light
  4. 4.Which drawing is the symbol for a bulb? (a) two or more cell symbols (b) one tall, one short bar (c) a circle with a cross (d) a plain rectangle
  5. 5.Which of these is measured in volts (V)? (a) energy used each second (b) voltage (c) the flow of charge (d) power
  6. 6.🔺 A current of 2.5 A flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
  7. 7.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) the bulb is unscrewed
  8. 8.🔺 An 8 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  9. 9.Which of these is an input? (a) an LED (b) a temperature sensor (c) a buzzer (d) a speaker
  10. 10.🔺 An 8 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  11. 11.⚠️ A cell gets hot when its + and − ends are joined by a bare wire. What is this called? (a) an open circuit (b) a short circuit (c) a parallel circuit (d) a safe circuit
  12. 12.True or false: many long-short pairs is the symbol for a battery. (a) False (b) True
  13. 13.🤖 “if (A AND B)” is true when … (a) only B is true (b) both are false (c) only A is true (d) both A and B are true
  14. 14.🔍 Which is the odd one out? (a) a turning knob (b) a push button (c) a temperature sensor (d) a speaker
  15. 15.🤖 Does a digital alarm clock usually have a microcontroller inside? (a) Yes (b) No
  16. 16.True or false: a safety pin is an insulator. (a) True (b) False
  17. 17.🔋 How many 1.5 V cells must be joined in series to give 4.5 V?
  18. 18.Which of these mainly makes movement? (a) a traffic signal (b) a mixer grinder (c) a toaster (d) a doorbell
  19. 19.🔍 Which is the odd one out? (a) count button presses (b) an LED lights up (c) decide if soil is dry (d) compare with a limit
  20. 20.Which of these is safe? (a) poke things in a socket (b) keep drinks far away (c) fly a kite near wires (d) touch a fallen wire
  21. 21.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 0 % (c) 25 % (d) 5 %
  22. 22.⚡ A 6 W device works on 12 V. What current does it take (in amperes)? =
  23. 23.⚠️ Why must we never touch switches with wet hands? (a) water makes it cold (b) it is just untidy (c) it spoils the paint (d) water carries current
  24. 24.💡 In a series circuit, how many paths does the current have? (a) one (b) none (c) one for each bulb (d) two
  25. 25.🔘 A cell and a bulb are joined to two side-by-side paths: path 1 has switches A and B one after another, path 2 has switch C. A is OFF, B is ON and C is ON. Does the bulb glow? (a) No (b) Yes
  26. 26.🧮 Three equal 75 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  27. 27.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 7 HIGH
    set pin 8 LOW
    set pin 8 LOW
    Is the LED ON or OFF at the end?     (a) ON (b) OFF
  28. 28.📶 A pin that reads a push button is set as … (a) an input (b) an output (c) a resistor (d) a battery
  29. 29.🔺 A current of 0.1 A flows when 0.3 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.📏 How many amperes (A) is 2700 mA? =
  31. 31.🧾 One “unit” on an electricity bill is … (a) 1 kilowatt-hour (kWh) (b) 1 watt (c) 1 volt (d) 1 ampere
  32. 32.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a copper wire across the gap. Does the bulb glow? (a) Yes (b) No
  33. 33.🔁 repeat 4 times { repeat 2 times { beep } }
    How many beeps are there?
  34. 34.True or false: “each gets the full volts” is true of a parallel circuit. (a) True (b) False
  35. 35.True or false: “one bulb out, all go out” is true of a series circuit. (a) False (b) True
  36. 36.True or false: to poke things in a socket is safe. (a) False (b) True
  37. 37.🔺 A 6 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  38. 38.💡 3 identical bulbs are joined in parallel (each on its own side-by-side path) with a battery and a closed switch on the main wire. Bulb 1 is taken out of its holder. How many bulbs glow?
  39. 39.⏱️ repeat 4 times { buzzer ON; wait 600 ms; buzzer OFF; wait 100 ms }
    How many milliseconds does this take in all?
  40. 40.True or false: a laptop uses very little power. (a) False (b) True

Answer key

  1. True
  2. buzzer
  3. does not light
  4. a circle with a cross
  5. voltage
  6. 8
  7. the bulb is unscrewed
  8. 2
  9. a temperature sensor
  10. 40
  11. a short circuit
  12. True
  13. both A and B are true
  14. a speaker
  15. Yes
  16. False
  17. 3
  18. a mixer grinder
  19. an LED lights up
  20. keep drinks far away
  21. 5 %
  22. 0.5
  23. water carries current
  24. one
  25. Yes
  26. 25
  27. ON
  28. an input
  29. 3
  30. 2.7
  31. 1 kilowatt-hour (kWh)
  32. Yes
  33. 8
  34. True
  35. True
  36. False
  37. 1.5
  38. 2
  39. 2800
  40. False

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