Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 443 · 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 battery lights 2 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) dimmer (b) brighter (c) the same
3. 3.Which of these means the circuit is closed? (a) a wire has come loose (b) the bulb is unscrewed (c) all wires are joined (d) a wire is cut
4. 4.🔺 A current of 0.1 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
5. 5.What does a push button do? (a) springs back when let go (b) closes when tipped over (c) closes near a magnet (d) slides side to side
6. 6.True or false: a line lifted at a gap is the symbol for a switch. (a) True (b) False
7. 7.⚡ A 2.5 W device works on 5 V. What current does it take (in amperes)? =
8. 8.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a dry cork across the gap. Does the bulb glow? (a) No (b) Yes
9. 9.True or false: on a cell, “the shorter symbol line” means the + (positive) end. (a) False (b) True
10. 10.💡 What does LED stand for? (a) light energy dial (b) light-emitting diode (c) low energy device (d) large electric dial
11. 11.🔁 What does a variable do in a program? (a) joins two wires (b) measures light (c) stores a value (d) blinks an LED
12. 12.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
13. 13.What does a tilt switch do? (a) closes when tipped over (b) slides side to side (c) works only while pressed (d) flips up or down
14. 14.Which drawing is the symbol for a junction? (a) two equal parallel lines (b) a circle with M inside (c) a dot where wires meet (d) a line lifted at a gap
15. 15.Which of these is a good habit? (a) share only needed data (b) tap unknown app links (c) reuse one password (d) post your live location
16. 16.Which of these is not safe? (a) fly kites in open fields (b) take cells out after use (c) use mains for a project (d) stay away from pylons
17. 17.🧩 Which component blows if current is high? (a) transistor (b) diode (c) fuse (d) LED
18. 18.⏱️ How many milliseconds is a wait of 0.3 seconds?
19. 19.🔺 A 2 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
20. 20.True or false: to run fans in empty rooms wastes electricity. (a) False (b) True
21. 21.🔍 An object is 255 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
22. 22.True or false: to warn of a gas leak, use a gas sensor. (a) True (b) False
23. 23.⚡ What does a doorbell mainly change electricity into? (a) sound (b) light (c) movement (d) heat
24. 24.🔁 x = 3
    repeat 2 times { x = x × 2 }
    What is x at the end?
25. 25.🌈 A resistor has the colour bands violet, blue, yellow. What is its value in kilo-ohms (kΩ)? =
26. 26.True or false: a plain rectangle is the symbol for a voltmeter. (a) False (b) True
27. 27.⚡ Which formula gives electric power? (a) P = V × I (b) P = V + I (c) P = I ÷ V (d) P = V ÷ I
28. 28.⚠️ Is it safe to poke things in a socket? (a) safe (b) not safe
29. 29.True or false: a washing machine usually has a microcontroller inside. (a) True (b) False
30. 30.Which of these is true of a series circuit? (a) one out, the rest glow (b) used in house wiring (c) many paths for current (d) one bulb out, all go out
31. 31.💡 A blue LED uses 3 V and should get 25 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
32. 32.🌈 A resistor has the colour bands orange, blue, red. What is its value in kilo-ohms (kΩ)? =
33. 33.True or false: a circle with A inside is the symbol for an ammeter. (a) False (b) True
34. 34.🔢 To get a sensor reading onto a phone, which is the LAST step? (a) the board reads it (b) it is sent by Wi-Fi (c) the cloud stores it (d) the app shows it
35. 35.🔘 Which kind of switch closes near a magnet? (a) a reed switch (b) a tilt switch (c) a toggle switch (d) a slide switch
36. 36.🔍 An object is 68 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
37. 37.Which of these gives us electricity? (a) a battery (b) a mobile phone (c) a computer (d) an air conditioner
38. 38.Which of these wastes electricity? (a) use daylight to read (b) switch off empty rooms (c) close the fridge quickly (d) use old filament bulbs
39. 39.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a series circuit (c) a closed circuit (d) a full circuit
40. 40.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)

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