Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 650 · 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 20 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
2. 2.📏 How many milliamperes (mA) make 1 ampere? (a) 100 (b) 1000 (c) 60 (d) 10
3. 3.🔘 Which kind of switch springs back when let go? (a) a reed switch (b) a push button (c) a tilt switch (d) a slide switch
4. 4.Which job needs a pump? (a) show the temperature (b) move water to plants (c) turn to an exact angle (d) spin a robot’s wheels
5. 5.⚠️ Is it safe to throw cells in a fire? (a) safe (b) not safe
6. 6.True or false: “many paths for current” is true of a series circuit. (a) False (b) True
7. 7.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
8. 8.🌐 Each reading a sensor sends is 20 bytes. How many bytes do 100 readings take?
9. 9.Which of these is the process? (a) a temperature reading (b) a buzzer beeps (c) the pump turns on (d) compare with a limit
10. 10.Which of these wastes electricity? (a) close the fridge quickly (b) use daylight to read (c) leave fridge door open (d) unplug idle chargers
11. 11.🔢 To get a sensor reading onto a phone, which is the FIRST step? (a) the app shows it (b) the sensor measures (c) the cloud stores it (d) the board reads it
12. 12.⏱️ loop forever { LED ON; wait 250 ms; LED OFF; wait 1000 ms }
    How many milliseconds does one blink (ON + OFF) take?
13. 13.True or false: on a cell, “the end with a bump” means the + (positive) end. (a) True (b) False
14. 14.🔋 Does a power station give electricity or use electricity? (a) uses electricity (b) gives electricity
15. 15.⏱️ How many milliseconds are in 1 second? (a) 10 (b) 100 (c) 60 (d) 1000
16. 16.🔍 Which is the odd one out? (a) change default passwords (b) install software updates (c) tap unknown app links (d) log out of shared phones
17. 17.💡 3 identical bulbs are joined in series with a 3 V battery (ideal wires). How many volts does each bulb get? =
18. 18.🌐 Is a plain wall switch an IoT device? (a) an IoT device (b) not an IoT device
19. 19.Which of these is a good habit? (a) read app permissions (b) share camera links (c) post your live location (d) keep factory passwords
20. 20.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an LED lamp (c) an oil lamp (d) a candle
21. 21.True or false: on an LED, the leg by the flat edge is the anode (+). (a) True (b) False
22. 22.🔋 2 identical 1.5 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
23. 23.🔁 What does a variable do in a program? (a) joins two wires (b) measures light (c) stores a value (d) blinks an LED
24. 24.⚠️ Is it safe to climb an electric pole? (a) not safe (b) safe
25. 25.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V × I (c) P = V + I (d) P = V ÷ I
26. 26.⚠️ Is it safe to fly a kite near wires? (a) not safe (b) safe
27. 27.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
28. 28.⏱️ loop forever { LED ON; wait 50 ms; LED OFF; wait 150 ms }
    How many times does the LED blink in 7 seconds?
29. 29.💡 3 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 1 is taken out of its holder. How many bulbs glow?
30. 30.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = I ÷ V (c) R = V ÷ I (d) R = V + I
31. 31.🔍 Which is the odd one out? (a) climb an electric pole (b) use a cable with cuts (c) stop if a part gets hot (d) touch a fallen wire
32. 32.💡 3 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 3 is taken out of its holder. How many bulbs glow?
33. 33.🔁 repeat 5 times { repeat 4 times { beep } }
    How many beeps are there?
34. 34.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a metal paper clip. Does the bulb glow? (a) Yes (b) No
35. 35.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
36. 36.🤖 if (light < 300 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 540 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
37. 37.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put aluminium foil across the gap. Does the bulb glow? (a) Yes (b) No
38. 38.🔘 A cell and a bulb are joined to 4 side-by-side paths with one switch on each path — A, B, C and D (parallel). A is ON, B is ON, C is ON and D is ON. Does the bulb glow? (a) No (b) Yes
39. 39.🔍 Which is the odd one out? (a) a street light (b) a ceiling fan (c) a tube light (d) an LED lamp
40. 40.🔋 A 9 V battery and three 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =

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