Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 738 · 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.🔍 Which is the odd one out? (a) stop if a part gets hot (b) keep drinks far away (c) poke things in a socket (d) build with an adult near
2. 2.🔢 To run one loop of a plant-watering program, what comes right after “compare with the limit”? (a) wait a few seconds (b) switch the pump on/off (c) read the soil sensor
3. 3.📏 How many milliamperes (mA) make 1 ampere? (a) 60 (b) 1000 (c) 10 (d) 100
4. 4.🔁 What does a variable do in a program? (a) joins two wires (b) blinks an LED (c) measures light (d) stores a value
5. 5.🔌 A gap of dry air between two wires acts as … (a) a conductor (b) a cell (c) an insulator (d) a switch that is ON
6. 6.💡 4 identical bulbs are joined in parallel across a 4.5 V battery (ideal wires). How many volts does each bulb get? =
7. 7.✏️ Why do engineers draw circuits with symbols? (a) quick and clear for all (b) to hide the circuit (c) to make it colourful (d) symbols are heavier
8. 8.True or false: to turn off unused gadgets is a risky habit. (a) True (b) False
9. 9.🔐 A smart-camera app asks for your school name and home address. What should you do? (a) type it all in (b) share it with friends (c) post it online (d) ask a parent first
10. 10.⚡ A 36 W device works on 24 V. What current does it take (in amperes)? =
11. 11.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 150 ms }
    How many times does the LED blink in 7 seconds?
12. 12.💡 Why is house wiring done in parallel? (a) so all go off together (b) to make bulbs dim (c) to save copper only (d) each gets full voltage
13. 13.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 7300 Ω resistor? (a) violet-orange-red (b) orange-violet-red (c) violet-orange-orange (d) violet-orange-brown
14. 14.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 HIGH
    set pin 8 HIGH
    set pin 7 LOW
    set pin 8 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF
15. 15.🔋 How many 1.2 V cells must be joined in series to give 9.6 V?
16. 16.🔍 Which is the odd one out? (a) build with an adult near (b) use mains for a project (c) fly a kite near wires (d) climb an electric pole
17. 17.Which drawing is the symbol for an ammeter? (a) a circle with V inside (b) a plain rectangle (c) a circle with A inside (d) a long and a short line
18. 18.⏱️ How many milliseconds is a wait of 4.4 seconds?
19. 19.🔐 Is it a good or a risky habit to turn off unused gadgets? (a) risky habit (b) good habit
20. 20.🌈 A resistor has the colour bands violet, white, black. What is its value (in ohms)?
21. 21.🧮 A 3.5 V battery is joined to 5 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
22. 22.🌈 A resistor has the colour bands yellow, white, yellow. What is its value in kilo-ohms (kΩ)? =
23. 23.📏 Which unit measures power? (a) watt (W) (b) ohm (Ω) (c) ampere (A) (d) volt (V)
24. 24.Which of these is a good habit? (a) keep factory passwords (b) accept every permission (c) ignore update messages (d) change default passwords
25. 25.🔍 Which is the odd one out? (a) an electric drill (b) a ceiling fan (c) an electric iron (d) a mixer grinder
26. 26.True or false: “a knob turned part way” is a digital signal. (a) False (b) True
27. 27.🌈 In the resistor colour code, which number does black stand for?
28. 28.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
29. 29.🧮 Resistors of 150 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
30. 30.Which job needs a motor? (a) spin a robot’s wheels (b) show the temperature (c) move water to plants (d) show a status light
31. 31.⏱️ How many milliseconds are in 1 second? (a) 1000 (b) 60 (c) 100 (d) 10
32. 32.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 5 V supply. What current flows (in mA)?
33. 33.📏 How many milliamperes (mA) is 2.9 A?
34. 34.⚡ What does a buzzer mainly change electricity into? (a) heat (b) movement (c) sound (d) light
35. 35.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter
36. 36.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V × I (d) P = V ÷ I
37. 37.🏠 Which is a smart-home example? (a) lights on from an app (b) a hand fan (c) a printed map (d) a candle in a jar
38. 38.🔍 Which is the odd one out? (a) a push button (b) a motor (c) a motion sensor (d) a temperature sensor
39. 39.🔺 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
40. 40.True or false: on an LED, the shorter leg is the cathode (−). (a) False (b) True

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