Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 409 · 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.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
2. 2.True or false: “bulbs share the voltage” is true of a series circuit. (a) False (b) True
3. 3.🔘 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 OFF, B is ON, C is OFF and D is OFF. Does the bulb glow? (a) No (b) Yes
4. 4.🔍 Which is the odd one out? (a) fly a kite near wires (b) touch a switch when wet (c) take cells out after use (d) use mains for a project
5. 5.🌐 Is a plain table fan an IoT device? (a) an IoT device (b) not an IoT device
6. 6.⚡ A 0.75 W device works on 1.5 V. What current does it take (in amperes)? =
7. 7.💡 4 identical bulbs are joined in series with a 4 V battery (ideal wires). How many volts does each bulb get? =
8. 8.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = I × R (c) V = I ÷ R (d) V = R ÷ I
9. 9.🤖 if (light < 400 AND motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 370 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
10. 10.True or false: “the room temperature” is an analog signal. (a) False (b) True
11. 11.💡 What happens if an LED is put in backwards? (a) it does not light (b) it lights brighter (c) it changes colour (d) it makes a sound
12. 12.⚠️ Is it safe to build with an adult near? (a) safe (b) not safe
13. 13.Which of these is safe? (a) poke things in a socket (b) climb an electric pole (c) throw cells in a fire (d) take cells out after use
14. 14.🗺️ In an input → process → output plan, is “count button presses” the input, the process or the output? (a) input (b) output (c) process
15. 15.🔋 Identical cells side by side (in parallel) give … (a) no voltage (b) the same voltage (c) half the voltage (d) double the voltage
16. 16.True or false: a tilt switch works only while pressed. (a) False (b) True
17. 17.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 ampere (c) 1 watt (d) 1 kilowatt-hour (kWh)
18. 18.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
19. 19.🧮 Resistors of 20 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
20. 20.🔐 Is it a good or a risky habit to install software updates? (a) good habit (b) risky habit
21. 21.💡 An LED is joined to a 5 V battery with no 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
22. 22.🧩 Which part changes electrical energy into sound? (a) a diode (b) a capacitor (c) a resistor (d) a buzzer
23. 23.⚡ What does an electric toy car mainly change electricity into? (a) heat (b) movement (c) light (d) sound
24. 24.✏️ In a circuit diagram, wires are usually drawn as … (a) little stars (b) wavy lines (c) dotted circles (d) straight lines
25. 25.Which of these is not safe? (a) touch a switch when wet (b) build with an adult near (c) fly kites in open fields (d) stop if a part gets hot
26. 26.🔌 Is an iron nail a conductor or an insulator? (a) an insulator (b) a conductor
27. 27.🗺️ In an input → process → output plan, is “a motion sensor signal” the input, the process or the output? (a) input (b) output (c) process
28. 28.🔌 Which metal is used for most electric wires at home? (a) plastic (b) rubber (c) glass (d) copper
29. 29.🧮 Three equal 75 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
30. 30.Which of these mainly gives out light? (a) a doorbell (b) a room heater (c) a tube light (d) a buzzer
31. 31.True or false: “a motion sensor signal” is the output. (a) True (b) False
32. 32.🔐 Why install updates on IoT devices? (a) they make it heavier (b) they change the colour (c) they fix security holes (d) they delete the Wi-Fi
33. 33.Which of these is an insulator? (a) a steel coin (b) a graphite rod (c) a wooden stick (d) a copper wire
34. 34.⏱️ How many milliseconds is a wait of 2.6 seconds?
35. 35.✏️ In a circuit diagram, which part is drawn as a dot where wires meet? (a) battery (b) ammeter (c) voltmeter (d) junction
36. 36.🔍 Which is the odd one out? (a) stay away from pylons (b) build with an adult near (c) take cells out after use (d) touch a fallen wire
37. 37.🔍 Which is the odd one out? (a) keep factory passwords (b) ignore update messages (c) accept every permission (d) turn off unused gadgets
38. 38.🔺 A current of 2 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
39. 39.⏱️ repeat 6 times { buzzer ON; wait 800 ms; buzzer OFF; wait 100 ms }
    How many milliseconds does this take in all?
40. 40.Which of these gives us electricity? (a) a computer (b) a television (c) a mobile phone (d) a bicycle dynamo

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