Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 899 · 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.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 3.5 V supply. What current flows (in mA)?
2. 2.⚠️ Someone is getting a shock and is still touching a wire. What should you do? (a) pull them by the hand (b) pour water on them (c) shout for an adult (d) wait and watch
3. 3.📏 In the water-pipe picture of a circuit, current is like … (a) the water pressure (b) the flow of water (c) a narrow pipe (d) the pipe colour
4. 4.🌐 Is a battery torch an IoT device? (a) not an IoT device (b) an IoT device
5. 5.✏️ In a cell symbol, which line is the + terminal? (a) the longer line (b) neither line (c) the shorter line (d) both lines
6. 6.⚡ What does a buzzer mainly change electricity into? (a) heat (b) sound (c) light (d) movement
7. 7.💡 Why does an LED need a resistor in series? (a) to store charge (b) to make it brighter (c) to limit the current (d) to change its colour
8. 8.🔗 Series or parallel circuit: “one out, the rest glow”? (a) parallel (b) series
9. 9.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) always zero (c) their sum (d) less than either one
10. 10.True or false: “own switch for each bulb” is true of a series circuit. (a) True (b) False
11. 11.Which of these is an output? (a) a temperature sensor (b) an LED (c) a light sensor (d) a motion sensor
12. 12.⚠️ Is it safe to take cells out after use? (a) not safe (b) safe
13. 13.⚡ What does a mixer grinder mainly change electricity into? (a) movement (b) sound (c) heat (d) light
14. 14.🔁 x = 2
    repeat 4 times { x = x × 2 }
    What is x at the end?
15. 15.💡 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
    Is the LED ON or OFF at the end? (a) ON (b) OFF
16. 16.🔍 An object is 306 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
17. 17.🔁 count = 4
    repeat 2 times { count = count + 5 }
    What is count at the end?
18. 18.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) bigger (c) stay the same (d) zero
19. 19.Which job needs a distance sensor? (a) warn of a gas leak (b) switch on with a clap (c) make a parking alarm (d) start a fan when hot
20. 20.🤖 if (temperature > 37) { show “Hot” } else if (temperature > 21) { show “Warm” } else { show “Cool” }
    The temperature is 26 °C. What is shown? (a) Hot (b) Cool (c) Warm
21. 21.✏️ In a circuit diagram, which part is drawn as a circle with V inside? (a) bulb (b) voltmeter (c) diode (d) switch
22. 22.🔋 How many 1.2 V cells must be joined in series to give 6 V?
23. 23.True or false: a fuse makes a beeping sound. (a) True (b) False
24. 24.True or false: “own switch for each bulb” is true of a parallel circuit. (a) True (b) False
25. 25.🔺 A current of 40 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
26. 26.🗺️ In an input → process → output plan, is “the pump turns on” the input, the process or the output? (a) process (b) output (c) input
27. 27.True or false: to run fans in empty rooms wastes electricity. (a) False (b) True
28. 28.⏱️ repeat 6 times { buzzer ON; wait 900 ms; buzzer OFF; wait 300 ms }
    How many milliseconds does this take in all?
29. 29.⚡ A 9 W device works on 9 V. What current does it take (in amperes)? =
30. 30.🔋 A 3 V battery and one 1.5 V cell are joined in series, all facing the same way. What is the total voltage (in volts)? =
31. 31.🔁 count = 5
    repeat 2 times { count = count + 7 }
    What is count at the end?
32. 32.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
33. 33.💡 A red LED uses 2 V and should get 25 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
34. 34.⏱️ repeat 5 times { buzzer ON; wait 400 ms; buzzer OFF; wait 400 ms }
    How many milliseconds does this take in all?
35. 35.True or false: a line lifted at a gap is the symbol for a switch. (a) True (b) False
36. 36.What does a toggle switch do? (a) closes when tipped over (b) flips up or down (c) works only while pressed (d) slides side to side
37. 37.💡 2 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. Does bulb 1 glow? (a) Yes (b) No
38. 38.⏱️ repeat 4 times { buzzer ON; wait 300 ms; buzzer OFF; wait 400 ms }
    How many milliseconds does this take in all?
39. 39.🔺 A current of 25 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
40. 40.True or false: on a cell, “the end with a bump” means the + (positive) end. (a) False (b) True

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