Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 755 · 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.⏱️ loop forever { LED ON; wait 300 ms; LED OFF; wait 50 ms }
   How many milliseconds does one blink (ON + OFF) take?
2. 2.🔺 A 6 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
3. 3.🔌 Is an LED an input or an output for a microcontroller? (a) input (b) output
4. 4.✏️ In a circuit diagram, wires are usually drawn as … (a) dotted circles (b) straight lines (c) wavy lines (d) little stars
5. 5.⚠️ Is it safe to fly kites in open fields? (a) not safe (b) safe
6. 6.🔍 Which is the odd one out? (a) a wind-up clock (b) a pencil sharpener (c) a smart energy meter (d) a battery torch
7. 7.🔁 count = 0
   repeat 8 times { count = count + 3 }
   What is count at the end?
8. 8.🔌 Is a temperature sensor an input or an output for a microcontroller? (a) input (b) output
9. 9.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a rubber band. Does the bulb glow? (a) No (b) Yes
10. 10.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
11. 11.🔘 A cell, a bulb and switches A, B and C are joined one after another in a single loop (series). A is ON, B is OFF and C is ON. Does the bulb glow? (a) Yes (b) No
12. 12.What does a thermistor do? (a) stores a little charge (b) makes a beeping sound (c) has coloured bands (d) senses how hot it is
13. 13.What does the phone app do? (a) reads values, decides (b) acts on a command (c) shows data to you (d) stores data online
14. 14.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
15. 15.💡 2 identical bulbs are in parallel and each one takes 0.1 A. What total current (in amperes) comes from the battery? =
16. 16.⏱️ What does “wait 500 ms” do? (a) waits 500 seconds (b) blinks 500 times (c) turns the LED off (d) pauses for half a second
17. 17.Which drawing is the symbol for a wire? (a) a straight line (b) a dot where wires meet (c) many long-short pairs (d) two or more cell symbols
18. 18.🔺 A current of 40 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
19. 19.🔍 Which is the odd one out? (a) a traffic signal (b) an LED lamp (c) a siren (d) a night lamp
20. 20.📏 In the water-pipe picture of a circuit, resistance is like … (a) a bigger tank (b) a narrow pipe (c) the flow of water (d) the water pressure
21. 21.✏️ In a circuit diagram, which part is drawn as a small empty box? (a) wire (b) cell (c) resistor (d) voltmeter
22. 22.Which of these saves electricity? (a) iron one shirt at a time (b) leave the TV on standby (c) unplug idle chargers (d) leave fridge door open
23. 23.⏱️ repeat 10 times { buzzer ON; wait 200 ms; buzzer OFF; wait 600 ms }
    How many milliseconds does this take in all?
24. 24.⚡ Power tells us … (a) energy used each second (b) the colour of light (c) the length of a wire (d) the size of a cell
25. 25.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
26. 26.Which drawing is the symbol for a capacitor? (a) a small empty box (b) triangle, bar and arrows (c) two equal parallel lines (d) a long and a short line
27. 27.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 3 V supply. What current flows (in mA)?
28. 28.🌈 A resistor has the colour bands yellow, brown, red. What is its value in kilo-ohms (kΩ)? =
29. 29.True or false: a mixer grinder mainly gives out light. (a) True (b) False
30. 30.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) zero (c) stay the same (d) bigger
31. 31.🌈 A resistor has the colour bands yellow, red, black. What is its value (in ohms)?
32. 32.Which of these is not an IoT device? (a) a Wi-Fi weather station (b) a Wi-Fi doorbell camera (c) a pencil sharpener (d) an app-controlled bulb
33. 33.Which of these is the process? (a) compare with a limit (b) the pump turns on (c) a light level reading (d) a temperature reading
34. 34.⚠️ Is it safe to dry your hands first? (a) not safe (b) safe
35. 35.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets smaller (d) gets bigger
36. 36.💡 4 identical bulbs are in parallel and each bulb has its own switch on its path. 2 of the switches are OFF and the rest are ON. How many bulbs glow?
37. 37.🤖 if (moisture < 40) { pump ON } else { pump OFF }
    The soil moisture sensor reads 25 %. What happens? (a) pump OFF (b) pump ON
38. 38.🔘 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 ON, B is OFF and C is OFF. Does the bulb glow? (a) No (b) Yes
39. 39.🔍 Which is the odd one out? (a) a glass marble (b) a metal paper clip (c) a paper strip (d) a wooden stick
40. 40.🤖 if (light < 400) { lamp ON } else { lamp OFF }
    The light sensor reads 308. What happens? (a) lamp OFF (b) lamp ON

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