Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 257 · 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.True or false: the voltmeter measures current. (a) False (b) True
2. 2.🔺 A 4 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
3. 3.🔍 Which is the odd one out? (a) touch a fallen wire (b) throw cells in a fire (c) stop if a part gets hot (d) open a phone charger
4. 4.Which job needs a buzzer? (a) open a gate to 90° (b) show the temperature (c) beep an alarm (d) turn to an exact angle
5. 5.Which of these saves electricity? (a) leave the TV on standby (b) use old filament bulbs (c) leave fridge door open (d) use LED lamps
6. 6.🔺 A current of 40 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
7. 7.⚠️ Is it safe to stay away from pylons? (a) safe (b) not safe
8. 8.🔘 A cell, a bulb and switches A, B, C and D are joined one after another in a single loop (series). A is OFF, B is OFF, C is OFF and D is OFF. Does the bulb glow? (a) Yes (b) No
9. 9.Which drawing is the symbol for a switch? (a) a circle with M inside (b) a circle with an X in it (c) a circle with V inside (d) a line lifted at a gap
10. 10.🔋 3 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
11. 11.🔌 Is a paper strip a conductor or an insulator? (a) an insulator (b) a conductor
12. 12.⚠️ Which power source should children use for electronics projects? (a) a mains extension board (b) a wall socket (c) a small battery pack (d) an inverter socket
13. 13.💡 A battery lights 5 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) the same (b) dimmer (c) brighter
14. 14.🔁 What must there be for a current to flow? (a) a broken path (b) a plastic gap (c) one loose end (d) a complete loop
15. 15.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) smaller (c) stay the same (d) zero
16. 16.🔋 6 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
17. 17.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 0 % (c) 5 % (d) 50 %
18. 18.🔺 A current of 20 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
19. 19.💡 An LED is joined to a 3 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) may burn out (c) lights up
20. 20.✏️ In a circuit diagram, which part is drawn as triangle, bar and arrows? (a) switch (b) diode (c) bulb (d) LED
21. 21.🔢 To get a sensor reading onto a phone, which comes first: “it is sent by Wi-Fi” or “the app shows it”? (a) it is sent by Wi-Fi (b) the app shows it
22. 22.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
23. 23.🌈 In the resistor colour code, which number does brown stand for?
24. 24.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the filament (c) the glass (d) the switch
25. 25.True or false: one tall, one short bar is the symbol for a battery. (a) False (b) True
26. 26.💡 An LED is joined to a 5 V battery through a 1000 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) lights up (b) does not light (c) may burn out
27. 27.Which of these is measured in volts (V)? (a) how much a part resists (b) power (c) the push of a cell (d) the flow of charge
28. 28.True or false: “a buzzer beeps” is the process. (a) False (b) True
29. 29.🔺 A 4.8 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
30. 30.⏱️ What does “wait 500 ms” do? (a) waits 500 seconds (b) pauses for half a second (c) blinks 500 times (d) turns the LED off
31. 31.🔍 Which sensor would you use to open blinds at sunrise? (a) a distance sensor (b) a light sensor (c) a motion sensor (d) a sound sensor
32. 32.🔗 Series or parallel circuit: “own switch for each bulb”? (a) parallel (b) series
33. 33.True or false: to build with an adult near is safe. (a) True (b) False
34. 34.True or false: on a cell, “usually the black wire” means the + (positive) end. (a) True (b) False
35. 35.True or false: to turn off unused gadgets is a good habit. (a) True (b) False
36. 36.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) − (negative) (b) + (positive)
37. 37.⚡ What do we call a flow of electric charge through a wire? (a) a magnet (b) friction (c) electric current (d) sound
38. 38.📏 How many watts (W) is 0.2 kW?
39. 39.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
40. 40.🤖 if (light < 300 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 520 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON

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