Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 995 · 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 is the odd one out? (a) a woollen thread (b) a dry cork (c) a plastic ruler (d) aluminium foil
2. 2.True or false: “compare with a limit” is the process. (a) False (b) True
3. 3.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in series (b) by Wi-Fi (c) not joined (d) in parallel
4. 4.🔋 On a cell, does “the flat end” mean the + end or the − end? (a) + (positive) (b) − (negative)
5. 5.🤖 if (moisture < 50) { pump ON } else { pump OFF }
   The soil moisture sensor reads 44 %. What happens? (a) pump OFF (b) pump ON
6. 6.⚙️ Which actuator would you use to open a gate to 90°? (a) a buzzer (b) a display (c) a motor (d) a servo motor
7. 7.📏 How many kilowatts (kW) is 2100 W? =
8. 8.📶 Digital or analog: a knob turned part way? (a) analog (b) digital
9. 9.🔐 Is it a good or a risky habit to share only needed data? (a) risky habit (b) good habit
10. 10.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. A gap in one wire is bridged by an iron nail. Does the bulb glow? (a) No (b) Yes
11. 11.Which of these is the input? (a) decide if soil is dry (b) a buzzer beeps (c) a light level reading (d) the fan starts
12. 12.💡 3 identical bulbs are joined in parallel across a 1.5 V battery (ideal wires). How many volts does each bulb get? =
13. 13.🌐 Is a fitness band with app an IoT device? (a) an IoT device (b) not an IoT device
14. 14.True or false: a steel spoon is a conductor. (a) False (b) True
15. 15.⚡ Which formula gives electric power? (a) P = V × I (b) P = V + I (c) P = I ÷ V (d) P = V ÷ I
16. 16.🔺 A current of 10 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
17. 17.🔺 A 1 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
18. 18.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 HIGH
    set pin 7 HIGH
    set pin 7 HIGH
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF
19. 19.True or false: “a single current path” is true of a parallel circuit. (a) True (b) False
20. 20.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. A gap in one wire is bridged by a steel coin. Does the bulb glow? (a) No (b) Yes
21. 21.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 50 ms }
    How many times does the LED blink in 9 seconds?
22. 22.Which of these is safe? (a) use mains for a project (b) dry your hands first (c) climb an electric pole (d) poke things in a socket
23. 23.🔍 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?
24. 24.🌈 In the resistor colour code, which number does green stand for?
25. 25.🔋 On a cell, does “the shorter symbol line” mean the + end or the − end? (a) + (positive) (b) − (negative)
26. 26.🔍 Which is the odd one out? (a) stay away from pylons (b) touch a switch when wet (c) build with an adult near (d) use small battery cells
27. 27.🔺 A 10 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
28. 28.True or false: a plastic ruler is an insulator. (a) False (b) True
29. 29.🧩 Which component makes things spin? (a) motor (b) potentiometer (c) capacitor (d) transistor
30. 30.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 5 V supply. What current flows (in mA)?
31. 31.What does a reed switch do? (a) stays where you flip it (b) slides side to side (c) flips up or down (d) closes near a magnet
32. 32.⚡ Power tells us … (a) the colour of light (b) the size of a cell (c) the length of a wire (d) energy used each second
33. 33.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 1900 ms }
    How many times does the LED blink in 14 seconds?
34. 34.🧮 A 4 V battery is joined to 8 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
35. 35.⚙️ What is an actuator? (a) a battery (b) a program (c) an output that acts (d) a sensor
36. 36.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) stays the same (c) becomes zero (d) gets bigger
37. 37.🧮 A 5 V battery is joined to 2 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
38. 38.🔺 A current of 25 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
39. 39.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
40. 40.🌈 A resistor has the colour bands white, black, orange. What is its value in kilo-ohms (kΩ)? =

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