Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 999 · 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.⏱️ How many milliseconds is a wait of 1.1 seconds?
2. 2.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 kilowatt-hour (kWh) (c) 1 watt (d) 1 volt
3. 3.What does a capacitor do? (a) senses how bright it is (b) smooths a wobbly supply (c) beeps for an alarm (d) is a resistance knob
4. 4.🔺 A current of 0.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
5. 5.🔍 Which sensor would you use to stop a robot near walls? (a) a light sensor (b) a temperature sensor (c) a distance sensor (d) a sound sensor
6. 6.📏 Which unit measures power? (a) ohm (Ω) (b) volt (V) (c) ampere (A) (d) watt (W)
7. 7.💡 Why does an LED need a resistor in series? (a) to store charge (b) to change its colour (c) to limit the current (d) to make it brighter
8. 8.🤖 if (temperature > 31) { show “Hot” } else if (temperature > 18) { show “Warm” } else { show “Cool” }
   The temperature is 23 °C. What is shown? (a) Hot (b) Warm (c) Cool
9. 9.True or false: on an LED, the longer leg is the cathode (−). (a) False (b) True
10. 10.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V + I (c) P = I ÷ V (d) P = V × I
11. 11.True or false: to use small battery cells is safe. (a) True (b) False
12. 12.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) gets smaller (c) gets bigger (d) stays the same
13. 13.True or false: “a buzzer beeps” is the process. (a) True (b) False
14. 14.Which of these is the input? (a) check if temp > 30 (b) compare with a limit (c) the fan starts (d) a motion sensor signal
15. 15.⏱️ What does “wait 500 ms” do? (a) turns the LED off (b) waits 500 seconds (c) pauses for half a second (d) blinks 500 times
16. 16.⏱️ How many milliseconds is a wait of 4.7 seconds?
17. 17.🔌 Is an LED an input or an output for a microcontroller? (a) input (b) output
18. 18.⚠️ A cell gets hot when its + and − ends are joined by a bare wire. What is this called? (a) a safe circuit (b) a short circuit (c) a parallel circuit (d) an open circuit
19. 19.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) both of them (c) it does not matter (d) only one
20. 20.Which job needs an LED? (a) spin a robot’s wheels (b) turn to an exact angle (c) show the temperature (d) show a status light
21. 21.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
22. 22.🧮 Four equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
23. 23.🔘 When a switch is ON, the circuit is … (a) closed (b) broken (c) cut (d) open
24. 24.Which of these is a risky habit? (a) share only needed data (b) cover unused cameras (c) install software updates (d) accept every permission
25. 25.🧩 A capacitor in a circuit can … (a) make light (b) store charge briefly (c) spin a wheel (d) measure heat
26. 26.🔢 To get a sensor reading onto a phone, what comes right after “the sensor measures”? (a) it is sent by Wi-Fi (b) the cloud stores it (c) the board reads it (d) the app shows it
27. 27.🔢 To run one loop of a plant-watering program, which comes first: “compare with the limit” or “switch the pump on/off”? (a) switch the pump on/off (b) compare with the limit
28. 28.True or false: a resistor limits the current. (a) True (b) False
29. 29.Which job is done by the USB port? (a) shows the board is on (b) connect sensors and LEDs (c) brings power and code (d) restarts the program
30. 30.Which drawing is the symbol for a bulb? (a) many long-short pairs (b) two equal parallel lines (c) a circle with a cross (d) triangle, bar and arrows
31. 31.Which of these usually has a microcontroller inside? (a) a candle (b) a washing machine (c) a wind-up toy (d) a hand pump
32. 32.Which of these mainly gives out heat? (a) a siren (b) a loudspeaker (c) a doorbell (d) a water heater
33. 33.🔌 Which metal is used for most electric wires at home? (a) copper (b) rubber (c) plastic (d) glass
34. 34.⚡ An 18 W device works on 9 V. What current does it take (in amperes)? =
35. 35.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
36. 36.🧩 Which component beeps for an alarm? (a) resistor (b) capacitor (c) potentiometer (d) buzzer
37. 37.🧮 A 20 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
38. 38.🔺 A current of 40 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
39. 39.🔋 On a cell, does “the flat end” mean the + end or the − end? (a) − (negative) (b) + (positive)
40. 40.Which of these is true of a parallel circuit? (a) bulbs share the voltage (b) a single current path (c) used in house wiring (d) a break stops every bulb

Free electronics lessons, practice and worksheets at talentjr.in/electronics-for-kids