Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 347 · 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.⏱️ A program says “wait 10000 ms”. How many seconds is that? =
2. 2.True or false: to close the fridge quickly saves electricity. (a) True (b) False
3. 3.🤖 if (light < 400) { lamp ON } else { lamp OFF }
   The light sensor reads 519. What happens? (a) lamp OFF (b) lamp ON
4. 4.💡 6 identical bulbs are in parallel and each bulb has its own switch on its path. 2 of the switches are OFF and the rest are ON. How many bulbs glow?
5. 5.🔁 total = 0
   for i = 1 to 3 { total = total + i }
   What is total at the end?
6. 6.True or false: a water heater mainly gives out heat. (a) True (b) False
7. 7.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = I ÷ V (c) R = V ÷ I (d) R = V + I
8. 8.🌈 A resistor has the colour bands brown, grey, red. What is its value in kilo-ohms (kΩ)? =
9. 9.🔋 How many 3 V cells must be joined in series to give 6 V?
10. 10.🔁 total = 0
    for i = 1 to 7 { total = total + i }
    What is total at the end?
11. 11.Which of these is true of a parallel circuit? (a) a break stops every bulb (b) bulbs share the voltage (c) a single current path (d) used in house wiring
12. 12.⏱️ How many milliseconds is a wait of 2.6 seconds?
13. 13.📏 In the water-pipe picture of a circuit, current is like … (a) a narrow pipe (b) the flow of water (c) the water pressure (d) the pipe colour
14. 14.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
15. 15.🤖 if (temperature > 25) { fan ON } else { fan OFF }
    The temperature sensor reads 24 °C. What happens? (a) fan OFF (b) fan ON
16. 16.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 4 V supply. What current flows (in mA)?
17. 17.🔌 Is a paper strip a conductor or an insulator? (a) an insulator (b) a conductor
18. 18.🤖 if (light < 200 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 520 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
19. 19.⚡ A solar panel changes which kind of energy into electricity? (a) wind energy (b) light energy (c) sound energy (d) chemical energy
20. 20.True or false: to change default passwords is a good habit. (a) True (b) False
21. 21.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) less than either one (c) always zero (d) their sum
22. 22.🌈 A resistor has the colour bands green, yellow, red. What is its value (in ohms)?
23. 23.True or false: to spot someone walking in, use a motion sensor. (a) False (b) True
24. 24.Which drawing is the symbol for a resistor? (a) a dot where wires meet (b) a plain rectangle (c) triangle, bar and arrows (d) one tall, one short bar
25. 25.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they keep glowing (b) they explode (c) they all go out (d) they get dimmer
26. 26.🤖 if (distance < 20) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 12 cm. What happens? (a) buzzer is silent (b) buzzer beeps
27. 27.🧩 Which component makes a beeping sound? (a) motor (b) buzzer (c) transistor (d) diode
28. 28.True or false: a torch mainly makes sound. (a) False (b) True
29. 29.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) a cell is taken out
30. 30.🔘 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 OFF and C is OFF. Does the bulb glow? (a) Yes (b) No
31. 31.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
32. 32.True or false: on a cell, “usually the black wire” means the + (positive) end. (a) False (b) True
33. 33.True or false: on an LED, the longer leg is the anode (+). (a) True (b) False
34. 34.⚡ What does a street light mainly change electricity into? (a) sound (b) heat (c) movement (d) light
35. 35.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
36. 36.⚡ A device works on 12 V and takes 0.5 A. What is its power (in watts)? =
37. 37.⚡ A device works on 6 V and takes 0.1 A. What is its power (in watts)? =
38. 38.🌐 Is a Wi-Fi weather station an IoT device? (a) an IoT device (b) not an IoT device
39. 39.🔌 Which part of a screwdriver should an electrician hold? (a) the metal tip (b) the steel shaft (c) the bare end (d) the plastic handle
40. 40.True or false: “a break stops every bulb” is true of a series circuit. (a) True (b) False

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