Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 107 · 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.🧮 Three equal 30 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
2. 2.What does the phone app do? (a) carries the data (b) shows data to you (c) measures the real world (d) reads values, decides
3. 3.⚠️ What protects home wiring by melting or tripping when too much current flows? (a) a bulb (b) a long wire (c) a fuse or MCB (d) a plug top
4. 4.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 25 % (c) 5 % (d) 50 %
5. 5.⏱️ loop forever { LED ON; wait 850 ms; LED OFF; wait 1150 ms }
   How many times does the LED blink in 10 seconds?
6. 6.🔺 In the V-I-R triangle, how do we find I? (a) I = V + R (b) I = R ÷ V (c) I = V ÷ R (d) I = V × R
7. 7.🧩 Which part changes electrical energy into movement? (a) a resistor (b) a fuse (c) a motor (d) an LED
8. 8.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V × I (d) P = V + I
9. 9.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 3 V supply. What current flows (in mA)?
10. 10.True or false: on a cell, “usually the black wire” means the − (negative) end. (a) False (b) True
11. 11.🧮 Two equal 50 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
12. 12.⏱️ loop forever { LED ON; wait 400 ms; LED OFF; wait 350 ms }
    How many milliseconds does one blink (ON + OFF) take?
13. 13.🌐 A soil sensor sends a reading to an app every 20 minutes. How many readings arrive in 3 hours?
14. 14.🔺 A current of 1.5 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
15. 15.Which of these is true of a series circuit? (a) a break stops every bulb (b) own switch for each bulb (c) many paths for current (d) one out, the rest glow
16. 16.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) switch off empty rooms (c) use daylight to read (d) use old filament bulbs
17. 17.🌐 What does IoT stand for? (a) Inside of Toys (b) Internet of Things (c) Input of Tools (d) Internet of Talk
18. 18.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
19. 19.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 8 HIGH
    set pin 8 LOW
    set pin 8 LOW
    Is the LED ON or OFF at the end? (a) OFF (b) ON
20. 20.⏱️ What does “wait 500 ms” do? (a) pauses for half a second (b) turns the LED off (c) blinks 500 times (d) waits 500 seconds
21. 21.Which of these has no microcontroller inside? (a) a smart watch (b) a digital thermometer (c) a hand pump (d) a toy robot
22. 22.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
23. 23.✏️ Why do engineers draw circuits with symbols? (a) to hide the circuit (b) quick and clear for all (c) to make it colourful (d) symbols are heavier
24. 24.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
25. 25.🔍 Which is the odd one out? (a) stay away from pylons (b) touch a switch when wet (c) throw cells in a fire (d) use mains for a project
26. 26.Which job needs a light sensor? (a) measure classroom noise (b) open blinds at sunrise (c) close a window in rain (d) water a dry plant
27. 27.⚠️ Is it safe to use mains for a project? (a) safe (b) not safe
28. 28.🧮 A 33 Ω resistor is joined in series with two equal 50 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
29. 29.🧮 Two equal 220 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
30. 30.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
31. 31.⚡ A 3 W device works on 1.5 V. What current does it take (in amperes)? =
32. 32.🔺 A 4.7 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
33. 33.🔗 Series or parallel circuit: “a break stops every bulb”? (a) parallel (b) series
34. 34.🧮 An 11 V battery is joined to 12 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
35. 35.🔐 Is it a good or a risky habit to set up with a parent? (a) risky habit (b) good habit
36. 36.🔺 A 20 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
37. 37.💡 A battery lights 5 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) dimmer (b) brighter (c) the same
38. 38.🔋 Does a generator give electricity or use electricity? (a) uses electricity (b) gives electricity
39. 39.Which of these is a conductor? (a) a plastic ruler (b) a graphite rod (c) a ceramic cup (d) a cotton thread
40. 40.⚡ A cell changes stored chemical energy into which kind of energy? (a) wind energy (b) sound energy (c) nuclear energy (d) electrical energy

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