Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 624 · 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.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 52 Ω resistor? (a) red-green-black (b) green-red-brown (c) blue-red-black (d) green-red-black
2. 2.Which job needs a buzzer? (a) turn to an exact angle (b) beep an alarm (c) move water to plants (d) open a gate to 90°
3. 3.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
   set pin 7 HIGH
   set pin 7 HIGH
   Is the LED ON or OFF at the end? (a) OFF (b) ON
4. 4.Which of these is a good habit? (a) share camera links (b) set a strong password (c) accept every permission (d) keep factory passwords
5. 5.🔍 A distance sensor sends a sound pulse and hears the echo 13 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
6. 6.🔺 A current of 0.25 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
7. 7.🔐 Is it a good or a risky habit to cover unused cameras? (a) good habit (b) risky habit
8. 8.🔺 A current of 20 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
9. 9.🔘 A cell and a bulb are joined to 2 side-by-side paths with one switch on each path — A and B (parallel). A is OFF and B is OFF. Does the bulb glow? (a) Yes (b) No
10. 10.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is OFF (c) all wires are joined (d) a wire is cut
11. 11.⚠️ What protects home wiring by melting or tripping when too much current flows? (a) a bulb (b) a fuse or MCB (c) a plug top (d) a long wire
12. 12.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an oil lamp (c) an LED lamp (d) a candle
13. 13.🔍 An object is 51 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
14. 14.🔘 Switch A is on the main wire next to the cell and the bulb; then the wire splits into two side-by-side paths, one with switch B and one with switch C. A is OFF, B is ON and C is ON. Does the bulb glow? (a) Yes (b) No
15. 15.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
16. 16.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
17. 17.🧮 A 33 Ω resistor is joined in series with two equal 20 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
18. 18.🔺 A 12 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
19. 19.🔋 What is a battery? (a) a switch with a lid (b) a kind of bulb (c) one single wire (d) two or more cells joined
20. 20.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 10 (b) 1024 (c) 1000 (d) 100
21. 21.What does a slide switch do? (a) flips up or down (b) stays where you flip it (c) works only while pressed (d) slides side to side
22. 22.🧮 Resistors of 10 Ω, 470 Ω, 150 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
23. 23.🔺 A current of 50 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
24. 24.True or false: one tall, one short bar is the symbol for a cell. (a) False (b) True
25. 25.Which of these is a good habit? (a) install software updates (b) accept every permission (c) post your live location (d) tap unknown app links
26. 26.True or false: “bulbs share the voltage” is true of a series circuit. (a) True (b) False
27. 27.Which of these gives us electricity? (a) a bicycle dynamo (b) a water pump (c) a washing machine (d) a computer
28. 28.🔁 count = 4
    repeat 7 times { count = count + 9 }
    What is count at the end?
29. 29.📶 Digital or analog: how bright a room is? (a) digital (b) analog
30. 30.🔌 Why are electric wires covered in plastic? (a) to make them heavy (b) plastic is an insulator (c) plastic makes current (d) plastic is a conductor
31. 31.True or false: “the fan starts” is the output. (a) False (b) True
32. 32.💡 In a series circuit, how many paths does the current have? (a) one for each bulb (b) one (c) none (d) two
33. 33.What does a transistor do? (a) beeps for an alarm (b) boosts a small signal (c) is a resistance knob (d) has coloured bands
34. 34.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
35. 35.🔺 A current of 0.1 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
36. 36.🗺️ Before building a project, what should you write down first? (a) the box colour (b) inputs and outputs (c) nothing at all (d) the final price
37. 37.🔺 A current of 50 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
38. 38.🧮 A 0.7 V battery is joined to 4 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
39. 39.True or false: a wind-up toy usually has a microcontroller inside. (a) True (b) False
40. 40.🔁 What does a variable do in a program? (a) measures light (b) stores a value (c) joins two wires (d) blinks an LED

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