Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 27 · 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 0.2 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
2. 2.🧭 Which part of a microcontroller board shows the board is on? (a) the power LED (b) the pins (c) the USB port (d) the voltage regulator
3. 3.🧩 Which component makes things spin? (a) buzzer (b) diode (c) transistor (d) motor
4. 4.✏️ Why do engineers draw circuits with symbols? (a) symbols are heavier (b) to make it colourful (c) quick and clear for all (d) to hide the circuit
5. 5.🌈 A resistor has the colour bands green, red, black. What is its value (in ohms)?
6. 6.🔋 Does a computer give electricity or use electricity? (a) uses electricity (b) gives electricity
7. 7.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
8. 8.True or false: a school bell mainly gives out light. (a) True (b) False
9. 9.Which of these is a conductor? (a) a glass marble (b) a copper wire (c) a rubber band (d) a plastic ruler
10. 10.🔍 Which is the odd one out? (a) a buzzer (b) an LED (c) a motion sensor (d) a small display
11. 11.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 97000 Ω resistor? (a) white-violet-orange (b) white-violet-yellow (c) white-violet-red (d) violet-white-orange
12. 12.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 100 ms }
    How many times does the LED blink in 6 seconds?
13. 13.💡 An LED is joined to a 3 V battery through a 470 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) may burn out (b) does not light (c) lights up
14. 14.⚡ Which formula gives electric power? (a) P = V × I (b) P = V + I (c) P = I ÷ V (d) P = V ÷ I
15. 15.🧾 Which lamp gives the same light for the least power? (a) a candle (b) a filament bulb (c) an oil lamp (d) an LED lamp
16. 16.🔺 A current of 10 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
17. 17.🔦 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) No (b) Yes
18. 18.🔺 A current of 0.1 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
19. 19.Which of these is an IoT device? (a) a paper calendar (b) a plain table fan (c) a Wi-Fi smart plug (d) a battery torch
20. 20.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
21. 21.🔋 On a cell, does “usually the black wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
22. 22.🔍 Which is the odd one out? (a) tap unknown app links (b) reuse one password (c) cover unused cameras (d) share the Wi-Fi key
23. 23.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) it does not matter (c) none (d) both of them
24. 24.Which of these is an insulator? (a) a safety pin (b) a brass key (c) a copper wire (d) a plastic straw
25. 25.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. Does the bulb glow? (a) Yes (b) No
26. 26.🔘 A bulb and a cell are joined through 6 switches one after another in a single loop (series). What is the smallest number of switches that must be ON to light the bulb?
27. 27.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) zero (c) stay the same (d) smaller
28. 28.🤖 if (temperature > 37) { show “Hot” } else if (temperature > 21) { show “Warm” } else { show “Cool” }
    The temperature is 38 °C. What is shown? (a) Hot (b) Cool (c) Warm
29. 29.What does a resistor do? (a) smooths a wobbly supply (b) makes a beeping sound (c) lets current go one way (d) has coloured bands
30. 30.⚡ What does a siren mainly change electricity into? (a) light (b) movement (c) heat (d) sound
31. 31.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a steel coin. Does the bulb glow? (a) Yes (b) No
32. 32.True or false: to switch off empty rooms saves electricity. (a) True (b) False
33. 33.🔍 Which is the odd one out? (a) an LED (b) a buzzer (c) a water pump (d) a push button
34. 34.📏 Which unit measures energy used each second? (a) volt (V) (b) watt (W) (c) ohm (Ω) (d) ampere (A)
35. 35.🧩 A capacitor in a circuit can … (a) store charge briefly (b) make light (c) spin a wheel (d) measure heat
36. 36.🔌 Why are electric wires covered in plastic? (a) to make them heavy (b) plastic is a conductor (c) plastic makes current (d) plastic is an insulator
37. 37.True or false: one tall, one short bar is the symbol for a junction. (a) False (b) True
38. 38.🌐 Is a Wi-Fi smart plug an IoT device? (a) not an IoT device (b) an IoT device
39. 39.True or false: “used in house wiring” is true of a series circuit. (a) False (b) True
40. 40.Which drawing is the symbol for a cell? (a) one tall, one short bar (b) triangle, bar and arrows (c) two equal parallel lines (d) two or more cell symbols

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