Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 128 · 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.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in series (b) in parallel (c) by Wi-Fi (d) not joined
2. 2.⚠️ Which power source should children use for electronics projects? (a) an inverter socket (b) a mains extension board (c) a wall socket (d) a small battery pack
3. 3.Which of these wastes electricity? (a) close the fridge quickly (b) unplug idle chargers (c) run fans in empty rooms (d) switch off empty rooms
4. 4.🔺 A current of 25 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
5. 5.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) − (negative) (b) + (positive)
6. 6.True or false: on a cell, “the end with a bump” means the + (positive) end. (a) False (b) True
7. 7.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a woollen thread across the gap. Does the bulb glow? (a) Yes (b) No
8. 8.🔌 Why are electric wires covered in plastic? (a) to make them heavy (b) plastic makes current (c) plastic is a conductor (d) plastic is an insulator
9. 9.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 64000 Ω resistor? (a) blue-yellow-red (b) blue-yellow-orange (c) yellow-blue-orange (d) blue-yellow-yellow
10. 10.True or false: to climb an electric pole is not safe. (a) False (b) True
11. 11.🔍 Which is the odd one out? (a) a mixer grinder (b) an LED lamp (c) an electric drill (d) a table fan
12. 12.🔍 Which is the odd one out? (a) a Wi-Fi smart plug (b) an app-controlled bulb (c) a pencil sharpener (d) a Wi-Fi doorbell camera
13. 13.🌐 How does a home IoT device usually send its data to the app? (a) over Wi-Fi (b) through a candle (c) by shouting (d) by post
14. 14.💡 What happens if an LED is put in backwards? (a) it does not light (b) it changes colour (c) it makes a sound (d) it lights brighter
15. 15.🔍 Which is the odd one out? (a) a motor (b) an LED (c) a keypad (d) a water pump
16. 16.True or false: “an alert on the phone” is the output. (a) False (b) True
17. 17.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
18. 18.True or false: “an alert on the phone” is the input. (a) True (b) False
19. 19.🔺 A current of 3 A flows when 36 V is joined across a resistor. What is its resistance (in ohms)?
20. 20.🔺 A 7.5 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
21. 21.🤖 Does a digital alarm clock usually have a microcontroller inside? (a) No (b) Yes
22. 22.🌈 A resistor has the colour bands orange, yellow, orange. What is its value in kilo-ohms (kΩ)? =
23. 23.Which of these uses electricity? (a) a solar panel (b) an air conditioner (c) a wind turbine (d) a generator
24. 24.🔋 How many 1.5 V cells must be joined in series to give 12 V?
25. 25.⏱️ repeat 8 times { buzzer ON; wait 600 ms; buzzer OFF; wait 400 ms }
    How many milliseconds does this take in all?
26. 26.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
27. 27.🧩 Which component lets current go one way? (a) LDR (b) diode (c) resistor (d) capacitor
28. 28.⚡ What does a toaster mainly change electricity into? (a) heat (b) movement (c) light (d) sound
29. 29.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a graphite rod. Does the bulb glow? (a) Yes (b) No
30. 30.🧮 A 1 V battery is joined to 2 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
31. 31.🔘 Which kind of switch flips up or down? (a) a reed switch (b) a push button (c) a toggle switch (d) a slide switch
32. 32.🌐 A soil sensor sends a reading to an app every 5 minutes. How many readings arrive in 3 hours?
33. 33.🧮 A 10 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)?
34. 34.🔌 Is a water pump an input or an output for a microcontroller? (a) input (b) output
35. 35.🌐 Is a battery torch an IoT device? (a) an IoT device (b) not an IoT device
36. 36.What does an LED do? (a) blows if current is high (b) senses how hot it is (c) beeps for an alarm (d) glows using little power
37. 37.💡 2 identical bulbs are joined in series with a 2 V battery (ideal wires). How many volts does each bulb get? =
38. 38.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
39. 39.True or false: on a cell, “the flat end” means the + (positive) end. (a) False (b) True
40. 40.Which of these is a risky habit? (a) change default passwords (b) install software updates (c) ignore update messages (d) turn off unused gadgets

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