Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 400 · 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) open a phone charger (b) poke things in a socket (c) touch a fallen wire (d) stay away from pylons
2. 2.Which job is done by the USB port? (a) connect sensors and LEDs (b) keeps the voltage steady (c) shows the board is on (d) brings power and code
3. 3.🔺 A current of 50 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
4. 4.True or false: to share camera links is a risky habit. (a) True (b) False
5. 5.🔺 A current of 50 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
6. 6.⏱️ loop forever { LED ON; wait 500 ms; LED OFF; wait 500 ms }
   How many times does the LED blink in 3 seconds?
7. 7.🔺 A current of 10 mA flows when 4.7 V is joined across a resistor. What is its resistance (in ohms)?
8. 8.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
9. 9.🌈 Which band is read first on a resistor? (a) the gold band (b) any band (c) the widest gap (d) the one nearest an end
10. 10.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
11. 11.🔘 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 ON and D is ON. Does the bulb glow? (a) No (b) Yes
12. 12.🏠 Which is a smart-home example? (a) a hand fan (b) a printed map (c) a candle in a jar (d) lights on from an app
13. 13.🧾 A 1000 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
14. 14.🧮 A 47 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
15. 15.🤖 if (light < 300 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 110 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
16. 16.🌐 A soil sensor sends a reading to an app every 20 minutes. How many readings arrive in 4 hours?
17. 17.Which of these has no microcontroller inside? (a) a microwave oven (b) a digital thermometer (c) a digital alarm clock (d) a plain wall switch
18. 18.🌈 A resistor has the colour bands white, yellow, black. What is its value (in ohms)?
19. 19.🔢 To run one loop of a plant-watering program, which comes first: “read the soil sensor” or “wait a few seconds”? (a) read the soil sensor (b) wait a few seconds
20. 20.🔢 To plan an electronics project, what comes right after “build it with an adult”? (a) draw the circuit diagram (b) pick a problem to solve (c) test it and fix it (d) list inputs and outputs
21. 21.🤖 “if (A AND B)” is true when … (a) both are false (b) only A is true (c) only B is true (d) both A and B are true
22. 22.🔘 A cell and a bulb are joined to 3 side-by-side paths with one switch on each path — A, B and C (parallel). A is OFF, B is ON and C is OFF. Does the bulb glow? (a) Yes (b) No
23. 23.Which of these is not safe? (a) stop if a part gets hot (b) fly kites in open fields (c) stay away from pylons (d) use a cable with cuts
24. 24.Which of these is the process? (a) a temperature reading (b) decide if soil is dry (c) a button press (d) a light level reading
25. 25.Which of these gives us electricity? (a) a mobile phone (b) a computer (c) a refrigerator (d) a solar panel
26. 26.🔢 To plan an electronics project, what comes right after “pick a problem to solve”? (a) test it and fix it (b) build it with an adult (c) list inputs and outputs (d) draw the circuit diagram
27. 27.🔘 When a switch is ON, the circuit is … (a) open (b) cut (c) closed (d) broken
28. 28.⏱️ What does “wait 500 ms” do? (a) turns the LED off (b) pauses for half a second (c) blinks 500 times (d) waits 500 seconds
29. 29.Which of these is measured in ohms (Ω)? (a) voltage (b) how much a part resists (c) energy used each second (d) power
30. 30.💡 4 identical bulbs are joined in parallel across a 3 V battery (ideal wires). How many volts does each bulb get? =
31. 31.🌈 A resistor has the colour bands grey, orange, red. What is its value in kilo-ohms (kΩ)? =
32. 32.🧮 A 0.8 V battery is joined to 4 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
33. 33.🔘 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 OFF and C is OFF. Does the bulb glow? (a) No (b) Yes
34. 34.⏱️ loop forever { LED ON; wait 200 ms; LED OFF; wait 50 ms }
    How many times does the LED blink in 1 second?
35. 35.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
36. 36.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
37. 37.💡 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
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF
38. 38.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a plastic straw across the gap. Does the bulb glow? (a) Yes (b) No
39. 39.💡 A battery lights 4 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
40. 40.Which of these wastes electricity? (a) close the fridge quickly (b) iron one shirt at a time (c) set the AC to 24 °C (d) unplug idle chargers

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