Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 293 · 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.🧮 Resistors of 50 Ω, 470 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
2. 2.🔘 A bulb and a cell are joined through 5 switches one after another in a single loop (series). What is the smallest number of switches that must be ON to light the bulb?
3. 3.🔢 To get a sensor reading onto a phone, what comes right after “the sensor measures”? (a) the cloud stores it (b) the board reads it (c) the app shows it (d) it is sent by Wi-Fi
4. 4.🌈 A resistor has the colour bands green, orange, red. What is its value in kilo-ohms (kΩ)? =
5. 5.🌈 In the resistor colour code, which number does red stand for?
6. 6.🔢 To get a sensor reading onto a phone, which comes first: “the app shows it” or “the sensor measures”? (a) the app shows it (b) the sensor measures
7. 7.🔺 A current of 50 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
8. 8.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
9. 9.🔍 Which is the odd one out? (a) a graphite rod (b) a wooden stick (c) an iron nail (d) a steel spoon
10. 10.🌐 In an IoT system, which part carries the data? (a) phone app (b) actuator (c) Wi-Fi (d) sensor
11. 11.🔺 A current of 40 mA flows when 13.2 V is joined across a resistor. What is its resistance (in ohms)?
12. 12.🔁 What does “count = count + 1” do? (a) sets count to 1 (b) takes 1 away (c) adds 1 to count (d) prints 1
13. 13.🔐 A smart speaker is always listening for its wake word. What is a sensible habit? (a) put it in the bathroom (b) let strangers use it (c) mute it when not in use (d) tell it your passwords
14. 14.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
15. 15.🌐 What does IoT stand for? (a) Input of Tools (b) Internet of Things (c) Internet of Talk (d) Inside of Toys
16. 16.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = I ÷ V (c) P = V × I (d) P = V + I
17. 17.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a dry cork across the gap. Does the bulb glow? (a) Yes (b) No
18. 18.True or false: “one bulb out, all go out” is true of a parallel circuit. (a) True (b) False
19. 19.True or false: to ignore update messages is a good habit. (a) False (b) True
20. 20.🔌 Which metal is used for most electric wires at home? (a) copper (b) rubber (c) plastic (d) glass
21. 21.📶 Digital or analog: a button: pressed or not? (a) digital (b) analog
22. 22.🧮 Three equal 150 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
23. 23.🔋 Does a cell give electricity or use electricity? (a) gives electricity (b) uses electricity
24. 24.⏱️ repeat 9 times { buzzer ON; wait 800 ms; buzzer OFF; wait 900 ms }
    How many milliseconds does this take in all?
25. 25.🔺 A 24 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
26. 26.💡 Why is house wiring done in parallel? (a) to save copper only (b) to make bulbs dim (c) each gets full voltage (d) so all go off together
27. 27.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
28. 28.⏱️ How many milliseconds is a wait of 1.5 seconds?
29. 29.⚠️ Which power source should children use for electronics projects? (a) an inverter socket (b) a mains extension board (c) a small battery pack (d) a wall socket
30. 30.🤖 if (light < 300 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 220 and motion is detected (true). What happens? (a) porch lamp OFF (b) porch lamp ON
31. 31.🧮 A 1.4 V battery is joined to 12 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
32. 32.True or false: “a single current path” is true of a parallel circuit. (a) True (b) False
33. 33.🤖 Does a wind-up toy usually have a microcontroller inside? (a) Yes (b) No
34. 34.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I × R (c) V = I + R (d) V = I ÷ R
35. 35.⚡ Power tells us … (a) the colour of light (b) the length of a wire (c) energy used each second (d) the size of a cell
36. 36.True or false: an LED stores a little charge. (a) True (b) False
37. 37.Which of these mainly gives out heat? (a) a night lamp (b) an electric iron (c) a street light (d) a ceiling fan
38. 38.True or false: a microcontroller runs many apps at once. (a) False (b) True
39. 39.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
40. 40.What does a tilt switch do? (a) springs back when let go (b) closes when tipped over (c) slides side to side (d) works only while pressed

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