Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 783 · 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.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
2. 2.🔺 A current of 50 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
3. 3.Which of these is true of a series circuit? (a) each gets the full volts (b) own switch for each bulb (c) bulbs share the voltage (d) many paths for current
4. 4.🔺 A current of 1.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
5. 5.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 2000 Ω resistor? (a) orange-red-red (b) red-black-orange (c) red-black-brown (d) red-black-red
6. 6.Which of these means the circuit is open? (a) a cell is taken out (b) all wires are joined (c) the switch is ON (d) the loop is complete
7. 7.🧩 Which component senses how bright it is? (a) diode (b) potentiometer (c) LDR (d) thermistor
8. 8.Which of these is an IoT device? (a) a plain wall switch (b) a wind-up clock (c) a paper calendar (d) a fitness band with app
9. 9.🔍 Which is the odd one out? (a) poke things in a socket (b) use mains for a project (c) use small battery cells (d) use a cable with cuts
10. 10.🔺 A current of 10 mA flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
11. 11.💡 A blue LED uses 3 V and should get 20 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
12. 12.🔋 Does a generator give electricity or use electricity? (a) uses electricity (b) gives electricity
13. 13.⚠️ Why must we never touch switches with wet hands? (a) water carries current (b) it is just untidy (c) water makes it cold (d) it spoils the paint
14. 14.Which of these is measured in watts (W)? (a) power (b) resistance (c) the push of a cell (d) how much a part resists
15. 15.🔐 Which is the strongest password for a home smart camera? (a) admin (b) password (c) Tiger#Lamp42!Moon (d) 123456
16. 16.Which of these is safe? (a) throw cells in a fire (b) climb an electric pole (c) use a cable with cuts (d) dry your hands first
17. 17.⚡ What does a toaster mainly change electricity into? (a) sound (b) light (c) heat (d) movement
18. 18.🔌 Which metal is used for most electric wires at home? (a) plastic (b) glass (c) rubber (d) copper
19. 19.🧭 Which part of a microcontroller board keeps the voltage steady? (a) the main chip (b) the voltage regulator (c) the USB port (d) the pins
20. 20.🔁 count = 1
    while (count < 9) { count = count + 4 }
    How many times does the loop run?
21. 21.Which job needs a servo motor? (a) spin a robot’s wheels (b) open a gate to 90° (c) move water to plants (d) beep an alarm
22. 22.🔌 Is a servo motor an input or an output for a microcontroller? (a) output (b) input
23. 23.🔺 A current of 20 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
24. 24.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = I ÷ V (c) P = V × I (d) P = V + I
25. 25.🧮 A 10 Ω resistor is joined in series with two equal 100 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
26. 26.🔺 A 4 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
27. 27.Which of these is true of a series circuit? (a) used in house wiring (b) many paths for current (c) own switch for each bulb (d) a single current path
28. 28.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a diode (c) a capacitor (d) a buzzer
29. 29.True or false: to use a cable with cuts is not safe. (a) False (b) True
30. 30.🔍 Which is the odd one out? (a) use mains for a project (b) build with an adult near (c) climb an electric pole (d) use a cable with cuts
31. 31.💡 4 identical bulbs are joined in series with a 4 V battery (ideal wires). How many volts does each bulb get? =
32. 32.⚡ A device works on 6 V and takes 0.1 A. What is its power (in watts)? =
33. 33.🔢 To run one loop of a plant-watering program, what comes right after “switch the pump on/off”? (a) read the soil sensor (b) compare with the limit (c) wait a few seconds
34. 34.🗺️ In an input → process → output plan, is “an alert on the phone” the input, the process or the output? (a) process (b) input (c) output
35. 35.⚠️ Is it safe to stop if a part gets hot? (a) safe (b) not safe
36. 36.True or false: a reed switch works only while pressed. (a) True (b) False
37. 37.⚡ A 0.75 W device works on 1.5 V. What current does it take (in amperes)? =
38. 38.🤖 Microcontroller or laptop: which one has a built-in keyboard? (a) microcontroller (b) laptop
39. 39.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3.5 V supply. What current flows (in mA)?
40. 40.Which job is done by the main chip? (a) connect sensors and LEDs (b) runs the program (c) keeps the voltage steady (d) shows the board is on

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