Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 634 · 40 questions

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.

1. 1.🔋 7 identical 3 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
2. 2.⏱️ repeat 7 times { buzzer ON; wait 600 ms; buzzer OFF; wait 200 ms }
   How many milliseconds does this take in all?
3. 3.Which drawing is the symbol for a switch? (a) a line lifted at a gap (b) two equal parallel lines (c) a plain rectangle (d) one tall, one short bar
4. 4.Which of these is a conductor? (a) a woollen thread (b) a glass marble (c) a ceramic cup (d) aluminium foil
5. 5.🔋 5 identical 1.5 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
6. 6.🤖 if (temperature > 32) { show “Hot” } else if (temperature > 25) { show “Warm” } else { show “Cool” }
   The temperature is 44 °C. What is shown? (a) Cool (b) Warm (c) Hot
7. 7.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 5 V supply. What current flows (in mA)?
8. 8.🔌 Why are electric wires covered in plastic? (a) plastic is a conductor (b) to make them heavy (c) plastic is an insulator (d) plastic makes current
9. 9.Which drawing is the symbol for a bulb? (a) a straight line (b) a circle with a cross (c) a circle with V inside (d) a dot where wires meet
10. 10.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 2400 Ω resistor? (a) red-yellow-red (b) red-yellow-brown (c) yellow-red-red (d) red-yellow-orange
11. 11.🤖 if (moisture < 50) { pump ON } else { pump OFF }
    The soil moisture sensor reads 32 %. What happens? (a) pump ON (b) pump OFF
12. 12.True or false: a digital alarm clock has no microcontroller inside. (a) True (b) False
13. 13.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
14. 14.True or false: a candle usually has a microcontroller inside. (a) False (b) True
15. 15.🔁 count = 1
    repeat 10 times { count = count + 4 }
    What is count at the end?
16. 16.🌈 A resistor has the colour bands red, brown, yellow. What is its value in kilo-ohms (kΩ)? =
17. 17.True or false: on an LED, the longer leg is the anode (+). (a) False (b) True
18. 18.⏱️ A program says “wait 4750 ms”. How many seconds is that? =
19. 19.🧮 Three equal 300 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
20. 20.🤖 if (distance < 20) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 13 cm. What happens? (a) buzzer beeps (b) buzzer is silent
21. 21.🔍 A distance sensor sends a sound pulse and hears the echo 6 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
22. 22.Which of these saves electricity? (a) leave the TV on standby (b) unplug idle chargers (c) leave fridge door open (d) use old filament bulbs
23. 23.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) their sum (c) always zero (d) less than either one
24. 24.🤖 Does a TV remote usually have a microcontroller inside? (a) No (b) Yes
25. 25.🧮 A 20 Ω resistor is joined in series with two equal 200 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
26. 26.🔘 Which kind of switch closes when tipped over? (a) a reed switch (b) a slide switch (c) a tilt switch (d) a push button
27. 27.🔍 Which sensor would you use to make a parking alarm? (a) a soil moisture sensor (b) a gas sensor (c) a motion sensor (d) a distance sensor
28. 28.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
29. 29.Which of these is true of a series circuit? (a) each gets the full volts (b) many paths for current (c) a single current path (d) one out, the rest glow
30. 30.True or false: a dot where wires meet is the symbol for a switch. (a) True (b) False
31. 31.📏 How many milliamperes (mA) make 1 ampere? (a) 60 (b) 1000 (c) 100 (d) 10
32. 32.⏱️ repeat 8 times { buzzer ON; wait 800 ms; buzzer OFF; wait 500 ms }
    How many milliseconds does this take in all?
33. 33.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in parallel (b) not joined (c) in series (d) by Wi-Fi
34. 34.True or false: a laptop has a built-in keyboard. (a) True (b) False
35. 35.🔘 Which kind of switch closes near a magnet? (a) a reed switch (b) a slide switch (c) a toggle switch (d) a push button
36. 36.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) − (negative) (b) + (positive)
37. 37.🔺 A current of 0.2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
38. 38.🔗 Series or parallel circuit: “each gets the full volts”? (a) series (b) parallel
39. 39.Which of these is true of a series circuit? (a) used in house wiring (b) each gets the full volts (c) one out, the rest glow (d) a break stops every bulb
40. 40.True or false: a ceramic cup is a conductor. (a) False (b) True

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