Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 7 · 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 is a risky habit? (a) read app permissions (b) turn off unused gadgets (c) cover unused cameras (d) post your live location
2. 2.🔺 A 10 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
3. 3.🤖 Microcontroller or laptop: which one has a built-in keyboard? (a) laptop (b) microcontroller
4. 4.🔐 Is it a good or a risky habit to read app permissions? (a) good habit (b) risky habit
5. 5.True or false: a buzzer mainly makes sound. (a) False (b) True
6. 6.💡 An LED is joined to a 6 V battery through a 470 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) may burn out (b) does not light (c) lights up
7. 7.True or false: “a single current path” is true of a parallel circuit. (a) False (b) True
8. 8.⏱️ A program says “wait 7000 ms”. How many seconds is that? =
9. 9.True or false: a tilt switch works only while pressed. (a) True (b) False
10. 10.Which of these is a conductor? (a) a paper strip (b) a plastic ruler (c) a steel spoon (d) a rubber eraser
11. 11.🔁 x = 3
    repeat 5 times { x = x × 2 }
    What is x at the end?
12. 12.What does a push button do? (a) stays where you flip it (b) flips up or down (c) works only while pressed (d) closes when tipped over
13. 13.💡 What happens if an LED is put in backwards? (a) it does not light (b) it makes a sound (c) it lights brighter (d) it changes colour
14. 14.⏱️ What does “wait 500 ms” do? (a) blinks 500 times (b) waits 500 seconds (c) pauses for half a second (d) turns the LED off
15. 15.🌈 A resistor has the colour bands orange, red, orange. What is its value (in ohms)?
16. 16.True or false: the ammeter is joined across a part. (a) True (b) False
17. 17.💡 5 identical bulbs are joined in series with a battery and a closed switch on the main wire. All the bulbs are in place. Does bulb 4 glow? (a) No (b) Yes
18. 18.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 1900 ms }
    How many times does the LED blink in 10 seconds?
19. 19.🧩 Which component beeps for an alarm? (a) LED (b) motor (c) capacitor (d) buzzer
20. 20.💡 A battery lights 2 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) the same (b) dimmer (c) brighter
21. 21.💡 A blue LED uses 3 V and should get 20 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
22. 22.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they explode (b) they keep glowing (c) they all go out (d) they get dimmer
23. 23.⚡ A device works on 1.5 V and takes 0.1 A. What is its power (in watts)? =
24. 24.💡 An LED is joined to a 6 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) may burn out (b) lights up (c) does not light
25. 25.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
26. 26.🔌 A gap of dry air between two wires acts as … (a) a cell (b) an insulator (c) a switch that is ON (d) a conductor
27. 27.🌐 Is a plain table fan an IoT device? (a) an IoT device (b) not an IoT device
28. 28.🧮 Resistors of 10 Ω and 470 Ω are joined in series. What is the total resistance (in ohms)?
29. 29.⚡ A 0.3 W device works on 3 V. What current does it take (in amperes)? =
30. 30.True or false: “a single current path” is true of a series circuit. (a) True (b) False
31. 31.🧮 Two resistors in parallel give a total that is … (a) always zero (b) more than either one (c) their sum (d) less than either one
32. 32.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = V + I (c) R = V ÷ I (d) R = I ÷ V
33. 33.🔌 Is a safety pin a conductor or an insulator? (a) a conductor (b) an insulator
34. 34.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 350 ms }
    How many times does the LED blink in 5 seconds?
35. 35.💡 4 identical bulbs are joined in series with a 6 V battery (ideal wires). How many volts does each bulb get? =
36. 36.🔍 Which sensor would you use to keep an incubator warm? (a) a sound sensor (b) a light sensor (c) a motion sensor (d) a temperature sensor
37. 37.What does a push button do? (a) slides side to side (b) flips up or down (c) closes when tipped over (d) springs back when let go
38. 38.🧮 Resistors of 220 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
39. 39.🧮 Five equal 250 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
40. 40.Which job needs a motor? (a) beep an alarm (b) show the temperature (c) spin a robot’s wheels (d) move water to plants

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