Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 74 · 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.⚠️ Is it safe to use mains for a project? (a) safe (b) not safe
2. 2.🔁 What must there be for a current to flow? (a) a plastic gap (b) one loose end (c) a broken path (d) a complete loop
3. 3.⏱️ A program says “wait 1000 ms”. How many seconds is that? =
4. 4.🔁 total = 0
   for i = 1 to 12 { total = total + i }
   What is total at the end?
5. 5.🌈 Which band is read first on a resistor? (a) the widest gap (b) the gold band (c) the one nearest an end (d) any band
6. 6.🔘 A cell and a bulb are joined to 2 side-by-side paths with one switch on each path — A and B (parallel). A is OFF and B is ON. Does the bulb glow? (a) Yes (b) No
7. 7.📏 How many amperes (A) is 970 mA? =
8. 8.🔍 Which is the odd one out? (a) iron one shirt at a time (b) use daylight to read (c) set the AC to 24 °C (d) unplug idle chargers
9. 9.⚠️ Who should be with you when you build a circuit? (a) a stranger online (b) a trusted adult (c) a younger child (d) nobody
10. 10.⚠️ What protects home wiring by melting or tripping when too much current flows? (a) a bulb (b) a long wire (c) a plug top (d) a fuse or MCB
11. 11.🔢 To run one loop of a plant-watering program, which is the LAST step? (a) read the soil sensor (b) switch the pump on/off (c) compare with the limit (d) wait a few seconds
12. 12.🧾 Which lamp gives the same light for the least power? (a) a candle (b) an LED lamp (c) a filament bulb (d) an oil lamp
13. 13.True or false: “each gets the full volts” is true of a parallel circuit. (a) True (b) False
14. 14.True or false: a microcontroller uses very little power. (a) False (b) True
15. 15.True or false: “bulbs share the voltage” is true of a parallel circuit. (a) False (b) True
16. 16.🧮 Two equal 10 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
17. 17.True or false: to spot someone walking in, use a motion sensor. (a) False (b) True
18. 18.🔋 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)? =
19. 19.🔍 Which is the odd one out? (a) build with an adult near (b) stay away from pylons (c) use small battery cells (d) fly a kite near wires
20. 20.🔍 Which is the odd one out? (a) an exhaust fan (b) an electric drill (c) an electric toy car (d) a room heater
21. 21.🔗 Series or parallel circuit: “bulbs share the voltage”? (a) series (b) parallel
22. 22.⚡ A 1.5 W device works on 6 V. What current does it take (in amperes)? =
23. 23.🔺 A current of 25 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
24. 24.🔋 Cells joined + to − in a row (series) give … (a) a bigger voltage (b) no voltage (c) the same voltage (d) a smaller voltage
25. 25.🔺 A current of 0.1 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
26. 26.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
27. 27.✏️ In a cell symbol, which line is the + terminal? (a) both lines (b) neither line (c) the shorter line (d) the longer line
28. 28.🔺 A current of 1 A flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
29. 29.True or false: on a cell, “the flat end” means the + (positive) end. (a) True (b) False
30. 30.🔍 For a microcontroller, is a sensor an input or an output? (a) a fuse (b) an output (c) a power source (d) an input
31. 31.True or false: a steel spoon is an insulator. (a) False (b) True
32. 32.⏱️ How many milliseconds are in 1 second? (a) 10 (b) 1000 (c) 60 (d) 100
33. 33.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a buzzer (c) a diode (d) a capacitor
34. 34.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a safety pin across the gap. Does the bulb glow? (a) No (b) Yes
35. 35.🔺 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
36. 36.💡 5 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 4 is taken out of its holder. Does bulb 2 glow? (a) Yes (b) No
37. 37.🔘 Two switches are in parallel (side by side). When does the bulb glow? (a) only when both are OFF (b) only when both are ON (c) when either is ON (d) never
38. 38.🔗 Series or parallel circuit: “a single current path”? (a) parallel (b) series
39. 39.💡 6 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 2 is taken out of its holder. How many bulbs glow?
40. 40.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?

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