Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 334 · 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.🔺 A current of 40 mA flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
2. 2.Which of these is an insulator? (a) aluminium foil (b) a steel spoon (c) an iron nail (d) a rubber band
3. 3.🤖 Microcontroller or laptop: which one has a built-in keyboard? (a) laptop (b) microcontroller
4. 4.🔘 What does a switch do in a circuit? (a) changes the voltage (b) stores current (c) opens or closes the loop (d) makes electricity
5. 5.🧩 Which component blows if current is high? (a) potentiometer (b) fuse (c) resistor (d) LED
6. 6.Which of these is an insulator? (a) a dry cork (b) a steel coin (c) aluminium foil (d) an iron nail
7. 7.Which of these is not an IoT device? (a) a fitness band with app (b) a Wi-Fi weather station (c) a battery torch (d) an app-controlled bulb
8. 8.True or false: a capacitor has coloured bands. (a) False (b) True
9. 9.Which of these is the input? (a) the pump turns on (b) check if temp > 30 (c) an alert on the phone (d) a button press
10. 10.True or false: on a cell, “the flat end” means the − (negative) end. (a) False (b) True
11. 11.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
12. 12.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) neither part (b) the if part (c) both parts (d) the else part
13. 13.🔍 Which sensor would you use to open blinds at sunrise? (a) a light sensor (b) a distance sensor (c) a rain sensor (d) a temperature sensor
14. 14.📏 How many watts (W) is 1.3 kW?
15. 15.🔍 An object is 238 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
16. 16.📏 In the water-pipe picture of a circuit, current is like … (a) the flow of water (b) a narrow pipe (c) the water pressure (d) the pipe colour
17. 17.🔺 A 3 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
18. 18.⚡ A device works on 5 V and takes 0.25 A. What is its power (in watts)? =
19. 19.🤖 if (temperature > 36) { show “Hot” } else if (temperature > 20) { show “Warm” } else { show “Cool” }
    The temperature is 38 °C. What is shown? (a) Warm (b) Cool (c) Hot
20. 20.Which drawing is the symbol for a switch? (a) triangle against a bar (b) a line lifted at a gap (c) a straight line (d) a circle with V inside
21. 21.🔍 Which is the odd one out? (a) an iron nail (b) a rubber band (c) a cotton thread (d) a dry cork
22. 22.🔺 A current of 20 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
23. 23.✏️ In a circuit diagram, which part is drawn as two or more cell symbols? (a) battery (b) voltmeter (c) LED (d) bulb
24. 24.True or false: a slide switch springs back when let go. (a) True (b) False
25. 25.What does a push button do? (a) springs back when let go (b) stays where you flip it (c) slides side to side (d) flips up or down
26. 26.🔺 A current of 2 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
27. 27.📏 How many amperes (A) is 440 mA? =
28. 28.Which of these is a risky habit? (a) change default passwords (b) share only needed data (c) turn off unused gadgets (d) reuse one password
29. 29.⏱️ What does “wait 500 ms” do? (a) turns the LED off (b) pauses for half a second (c) waits 500 seconds (d) blinks 500 times
30. 30.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
31. 31.🔘 A cell, a bulb and switches A and B are joined one after another in a single loop (series). A is OFF and B is OFF. Does the bulb glow? (a) No (b) Yes
32. 32.🔐 Is it a good or a risky habit to read app permissions? (a) good habit (b) risky habit
33. 33.🧮 Three equal 30 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
34. 34.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
35. 35.True or false: a toggle switch stays where you flip it. (a) False (b) True
36. 36.🌈 A resistor has the colour bands blue, brown, yellow. What is its value in kilo-ohms (kΩ)? =
37. 37.🔍 Which is the odd one out? (a) a water heater (b) an electric iron (c) a toaster (d) a tube light
38. 38.⏱️ How many milliseconds are in 1 second? (a) 60 (b) 1000 (c) 10 (d) 100
39. 39.🔺 A current of 1 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
40. 40.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 5700 Ω resistor? (a) violet-green-red (b) green-violet-red (c) green-violet-brown (d) green-violet-orange

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