Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 126 · 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 of these has no microcontroller inside? (a) a wind-up toy (b) a washing machine (c) a digital alarm clock (d) a toy robot
2. 2.🌈 A resistor has the colour bands white, brown, yellow. What is its value in kilo-ohms (kΩ)? =
3. 3.✏️ In a cell symbol, which line is the + terminal? (a) the shorter line (b) both lines (c) neither line (d) the longer line
4. 4.True or false: on an LED, the longer leg is the anode (+). (a) True (b) False
5. 5.🗺️ Before building a project, what should you write down first? (a) inputs and outputs (b) the final price (c) the box colour (d) nothing at all
6. 6.Which of these is not safe? (a) use small battery cells (b) keep drinks far away (c) dry your hands first (d) poke things in a socket
7. 7.🤖 if (light < 200 OR motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 270 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON
8. 8.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a rubber band across the gap. Does the bulb glow? (a) Yes (b) No
9. 9.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
   set pin 7 LOW
   set pin 8 HIGH
   set pin 7 LOW
   set pin 8 LOW
   set pin 8 LOW
   Is the LED ON or OFF at the end? (a) ON (b) OFF
10. 10.True or false: “a break stops every bulb” is true of a series circuit. (a) True (b) False
11. 11.💡 A blue LED uses 3 V and should get 25 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
12. 12.⚠️ Is it safe to poke things in a socket? (a) not safe (b) safe
13. 13.🤖 “if (A AND B)” is true when … (a) only A is true (b) both A and B are true (c) both are false (d) only B is true
14. 14.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) bigger (c) zero (d) smaller
15. 15.🤖 if (temperature > 32) { fan ON } else { fan OFF }
    The temperature sensor reads 39 °C. What happens? (a) fan OFF (b) fan ON
16. 16.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
17. 17.True or false: a candle usually has a microcontroller inside. (a) True (b) False
18. 18.⚡ Which formula gives electric power? (a) P = V × I (b) P = V ÷ I (c) P = V + I (d) P = I ÷ V
19. 19.Which job is done by the power LED? (a) keeps the voltage steady (b) brings power and code (c) connect sensors and LEDs (d) shows the board is on
20. 20.📏 In the water-pipe picture of a circuit, voltage is like … (a) the tap handle (b) the water tank lid (c) the water pressure (d) the pipe colour
21. 21.🧩 Which component smooths a wobbly supply? (a) buzzer (b) LED (c) fuse (d) capacitor
22. 22.Which of these is measured in ohms (Ω)? (a) energy used each second (b) resistance (c) voltage (d) current
23. 23.⏱️ What does “wait 500 ms” do? (a) waits 500 seconds (b) turns the LED off (c) pauses for half a second (d) blinks 500 times
24. 24.🔐 Is it a good or a risky habit to accept every permission? (a) risky habit (b) good habit
25. 25.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 2.75 V supply. What current flows (in mA)?
26. 26.🤖 if (sound > 70) { red LED ON } else { green LED ON }
    The sound sensor reads 75. What happens? (a) green LED ON (b) red LED ON
27. 27.🔋 What is a battery? (a) a switch with a lid (b) two or more cells joined (c) one single wire (d) a kind of bulb
28. 28.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
29. 29.Which of these is the output? (a) a soil moisture reading (b) a buzzer beeps (c) compare with a limit (d) a motion sensor signal
30. 30.✏️ Why do engineers draw circuits with symbols? (a) quick and clear for all (b) to make it colourful (c) symbols are heavier (d) to hide the circuit
31. 31.Which job needs a light sensor? (a) make a parking alarm (b) open blinds at sunrise (c) water a dry plant (d) spot someone walking in
32. 32.⚠️ Is it safe to touch a switch when wet? (a) safe (b) not safe
33. 33.🧮 Three equal 150 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
34. 34.🔢 To get a sensor reading onto a phone, what comes right after “it is sent by Wi-Fi”? (a) the sensor measures (b) the app shows it (c) the board reads it (d) the cloud stores it
35. 35.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V + I (c) R = V ÷ I (d) R = V × I
36. 36.⚠️ A cell gets hot when its + and − ends are joined by a bare wire. What is this called? (a) a safe circuit (b) an open circuit (c) a parallel circuit (d) a short circuit
37. 37.Which of these is a conductor? (a) a plastic straw (b) a brass key (c) a rubber eraser (d) a plastic ruler
38. 38.🧮 Four equal 80 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
39. 39.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
40. 40.What does a slide switch do? (a) works only while pressed (b) flips up or down (c) slides side to side (d) closes when tipped over

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