Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 225 · 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 a cell, does “usually the black wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
2. 2.True or false: energy used each second is measured in ohms (Ω). (a) True (b) False
3. 3.🔺 A current of 40 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
4. 4.🔁 repeat 3 times { repeat 6 times { beep } }
   How many beeps are there?
5. 5.🧮 Two resistors in parallel give a total that is … (a) always zero (b) less than either one (c) more than either one (d) their sum
6. 6.⚠️ A cell gets hot when its + and − ends are joined by a bare wire. What is this called? (a) an open circuit (b) a safe circuit (c) a parallel circuit (d) a short circuit
7. 7.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) a candle (c) an oil lamp (d) an LED lamp
8. 8.True or false: to use mains for a project is safe. (a) False (b) True
9. 9.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
10. 10.True or false: a microcontroller has no screen of its own. (a) False (b) True
11. 11.True or false: “how loud a sound is” is an analog signal. (a) True (b) False
12. 12.📏 In the water-pipe picture of a circuit, voltage is like … (a) the pipe colour (b) the water pressure (c) the water tank lid (d) the tap handle
13. 13.💡 Why does an LED need a resistor in series? (a) to limit the current (b) to change its colour (c) to make it brighter (d) to store charge
14. 14.🌈 Which band is read first on a resistor? (a) the widest gap (b) any band (c) the one nearest an end (d) the gold band
15. 15.🤖 if (moisture < 30) { pump ON } else { pump OFF }
    The soil moisture sensor reads 37 %. What happens? (a) pump OFF (b) pump ON
16. 16.What does a tilt switch do? (a) works only while pressed (b) flips up or down (c) closes when tipped over (d) slides side to side
17. 17.Which of these wastes electricity? (a) use LED lamps (b) switch off empty rooms (c) use old filament bulbs (d) unplug idle chargers
18. 18.🔋 How many 3 V cells must be joined in series to give 12 V?
19. 19.True or false: an electric kettle mainly makes sound. (a) False (b) True
20. 20.🧩 Which part changes electrical energy into movement? (a) a resistor (b) a motor (c) an LED (d) a fuse
21. 21.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) not joined (b) by Wi-Fi (c) in parallel (d) in series
22. 22.🔍 Which is the odd one out? (a) an electric iron (b) a street light (c) a rice cooker (d) a room heater
23. 23.🔌 Is a dry cork a conductor or an insulator? (a) a conductor (b) an insulator
24. 24.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
25. 25.🤖 Microcontroller or laptop: which one has no screen of its own? (a) laptop (b) microcontroller
26. 26.⏱️ How many milliseconds are in 1 second? (a) 1000 (b) 60 (c) 100 (d) 10
27. 27.⚡ A 4.5 W device works on 3 V. What current does it take (in amperes)? =
28. 28.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 8 LOW
    set pin 8 LOW
    set pin 7 LOW
    set pin 8 HIGH
    Is the LED ON or OFF at the end? (a) OFF (b) ON
29. 29.📏 How many milliamperes (mA) make 1 ampere? (a) 60 (b) 1000 (c) 10 (d) 100
30. 30.🧩 Which component lets current go one way? (a) transistor (b) potentiometer (c) capacitor (d) diode
31. 31.🤖 How does a new program get onto a microcontroller board? (a) typed on the chip (b) uploaded over USB (c) drawn with a pen (d) sent by sound
32. 32.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) both of them (c) none (d) only one
33. 33.⏱️ How many milliseconds is a wait of 1.7 seconds?
34. 34.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
35. 35.🔺 A current of 2.5 A flows when 15 V is joined across a resistor. What is its resistance (in ohms)?
36. 36.True or false: two or more cell symbols is the symbol for a battery. (a) False (b) True
37. 37.Which of these is true of a parallel circuit? (a) a break stops every bulb (b) one bulb out, all go out (c) many paths for current (d) a single current path
38. 38.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
39. 39.Which of these is a risky habit? (a) set up with a parent (b) cover unused cameras (c) change default passwords (d) ignore update messages
40. 40.📏 How many amperes (A) is 1700 mA? =

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