Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 772 · 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.True or false: to measure classroom noise, use a sound sensor. (a) False (b) True
2. 2.🧩 Which part changes electrical energy into movement? (a) a fuse (b) an LED (c) a resistor (d) a motor
3. 3.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V × I (c) P = I ÷ V (d) P = V + I
4. 4.True or false: a graphite rod is an insulator. (a) False (b) True
5. 5.🔺 A current of 3 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
6. 6.🤖 Does a bicycle bell usually have a microcontroller inside? (a) Yes (b) No
7. 7.True or false: the ammeter measures current. (a) True (b) False
8. 8.🧩 Which component lets current go one way? (a) transistor (b) capacitor (c) diode (d) potentiometer
9. 9.Which of these wastes electricity? (a) leave fridge door open (b) use LED lamps (c) switch off empty rooms (d) unplug idle chargers
10. 10.🔺 A current of 40 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
11. 11.⚙️ Which actuator would you use to spin a robot’s wheels? (a) a servo motor (b) a buzzer (c) an LED (d) a motor
12. 12.🔐 A smart speaker is always listening for its wake word. What is a sensible habit? (a) put it in the bathroom (b) mute it when not in use (c) tell it your passwords (d) let strangers use it
13. 13.🔁 x = 1
    repeat 5 times { x = x × 2 }
    What is x at the end?
14. 14.🔍 Which is the odd one out? (a) use daylight to read (b) use old filament bulbs (c) use LED lamps (d) switch off empty rooms
15. 15.Which of these is an insulator? (a) a rubber band (b) a safety pin (c) a steel spoon (d) a steel coin
16. 16.💡 A blue LED uses 3 V and should get 25 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
17. 17.🔺 A current of 25 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
18. 18.What does the microcontroller do? (a) carries the data (b) measures the real world (c) reads values, decides (d) acts on a command
19. 19.🔺 A current of 25 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
20. 20.⚠️ About how many volts do home sockets in India supply? (a) 1.5 V (b) 9 V (c) 230 V (d) 12 V
21. 21.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
22. 22.🌐 What does IoT stand for? (a) Internet of Things (b) Inside of Toys (c) Internet of Talk (d) Input of Tools
23. 23.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
24. 24.🤖 if (light < 300 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 480 and motion is detected (true). What happens? (a) porch lamp OFF (b) porch lamp ON
25. 25.⚡ Power tells us … (a) the length of a wire (b) the colour of light (c) the size of a cell (d) energy used each second
26. 26.🔁 What does “count = count + 1” do? (a) takes 1 away (b) sets count to 1 (c) prints 1 (d) adds 1 to count
27. 27.🔋 How many 1.2 V cells must be joined in series to give 7.2 V?
28. 28.💡 Why does an LED need a resistor in series? (a) to make it brighter (b) to store charge (c) to limit the current (d) to change its colour
29. 29.True or false: to warn of a gas leak, use a motion sensor. (a) False (b) True
30. 30.🔁 total = 0
    for i = 1 to 10 { total = total + i }
    What is total at the end?
31. 31.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
32. 32.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. A gap in one wire is bridged by a plastic straw. Does the bulb glow? (a) No (b) Yes
33. 33.Which drawing is the symbol for a motor? (a) triangle, bar and arrows (b) a circle with M inside (c) a straight line (d) a circle with an X in it
34. 34.🔌 A gap of dry air between two wires acts as … (a) a cell (b) a switch that is ON (c) a conductor (d) an insulator
35. 35.🔐 Who should decide which smart devices go in a child’s room? (a) a parent or guardian (b) the app’s adverts (c) nobody at all (d) an online stranger
36. 36.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = V × R (c) I = V + R (d) I = R ÷ V
37. 37.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) − (negative) (b) + (positive)
38. 38.True or false: “a light level reading” is the input. (a) False (b) True
39. 39.Which of these is an insulator? (a) a steel coin (b) a steel spoon (c) a rubber eraser (d) aluminium foil
40. 40.🔘 A cell and a bulb are joined to 2 side-by-side paths with one switch on each path — A and B (parallel). A is OFF and B is ON. Does the bulb glow? (a) No (b) Yes

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