Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 57 · 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.✏️ Why do engineers draw circuits with symbols? (a) symbols are heavier (b) to make it colourful (c) quick and clear for all (d) to hide the circuit
2. 2.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
3. 3.🔺 A current of 50 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
4. 4.🔺 A current of 20 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
5. 5.⚡ A device works on 24 V and takes 1 A. What is its power (in watts)? =
6. 6.True or false: to poke things in a socket is safe. (a) False (b) True
7. 7.🔍 Which is the odd one out? (a) a traffic signal (b) a room heater (c) a torch (d) a night lamp
8. 8.⏱️ loop forever { LED ON; wait 300 ms; LED OFF; wait 1700 ms }
   How many times does the LED blink in 4 seconds?
9. 9.⚠️ Which power source should children use for electronics projects? (a) a small battery pack (b) a mains extension board (c) an inverter socket (d) a wall socket
10. 10.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
11. 11.⚡ What does a rice cooker mainly change electricity into? (a) sound (b) light (c) movement (d) heat
12. 12.True or false: “one bulb out, all go out” is true of a series circuit. (a) False (b) True
13. 13.🔋 What should you do with used-up cells? (a) bury them in soil (b) give them for recycling (c) throw them in a fire (d) cut them open
14. 14.True or false: “compare with a limit” is the output. (a) False (b) True
15. 15.⏱️ How many milliseconds is a wait of 1.4 seconds?
16. 16.🧮 Five equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
17. 17.Which of these is an input? (a) a servo motor (b) an LED (c) a speaker (d) a push button
18. 18.🔌 Is a motor an input or an output for a microcontroller? (a) input (b) output
19. 19.Which of these is an insulator? (a) an iron nail (b) a safety pin (c) a copper wire (d) a wooden stick
20. 20.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
21. 21.🔍 Which sensor would you use to start a fan when hot? (a) a soil moisture sensor (b) a distance sensor (c) a gas sensor (d) a temperature sensor
22. 22.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) zero (c) bigger (d) stay the same
23. 23.True or false: an LED lamp mainly gives out heat. (a) False (b) True
24. 24.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
25. 25.🔁 count = 5
    while (count < 11) { count = count + 2 }
    How many times does the loop run?
26. 26.Which job needs a distance sensor? (a) spot someone walking in (b) make a parking alarm (c) open blinds at sunrise (d) switch on lamps at dusk
27. 27.True or false: on a cell, “usually the red wire” means the + (positive) end. (a) False (b) True
28. 28.🔍 Which is the odd one out? (a) open a phone charger (b) build with an adult near (c) dry your hands first (d) stop if a part gets hot
29. 29.Which of these uses electricity? (a) a generator (b) a battery (c) a water pump (d) a wind turbine
30. 30.True or false: a buzzer mainly makes movement. (a) True (b) False
31. 31.⚙️ What is an actuator? (a) a battery (b) an output that acts (c) a sensor (d) a program
32. 32.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) stays the same (c) gets smaller (d) gets bigger
33. 33.💡 A battery lights 4 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) the same (b) dimmer (c) brighter
34. 34.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) neither part (b) the else part (c) the if part (d) both parts
35. 35.🧩 Which component smooths a wobbly supply? (a) potentiometer (b) LDR (c) thermistor (d) capacitor
36. 36.🔍 Which sensor would you use to switch on lamps at dusk? (a) a temperature sensor (b) a light sensor (c) a soil moisture sensor (d) a rain sensor
37. 37.🔍 Which sensor would you use to close a window in rain? (a) a light sensor (b) a rain sensor (c) a temperature sensor (d) a motion sensor
38. 38.🔁 What does “count = count + 1” do? (a) adds 1 to count (b) sets count to 1 (c) prints 1 (d) takes 1 away
39. 39.Which of these gives us electricity? (a) an air conditioner (b) a power station (c) a computer (d) a water pump
40. 40.🔋 Does a wind turbine give electricity or use electricity? (a) uses electricity (b) gives electricity

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