Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 496 · 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.🤖 if (distance < 15) { buzzer beeps } else { buzzer is silent }
   The distance sensor reads 17 cm. What happens? (a) buzzer beeps (b) buzzer is silent
2. 2.Which of these is not an IoT device? (a) a Wi-Fi smart plug (b) an app-controlled bulb (c) a Wi-Fi weather station (d) a pencil sharpener
3. 3.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
4. 4.🔋 2 identical 1.5 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
5. 5.Which of these mainly gives out heat? (a) a traffic signal (b) a table fan (c) an electric iron (d) a siren
6. 6.🔁 What does a variable do in a program? (a) blinks an LED (b) joins two wires (c) measures light (d) stores a value
7. 7.🔘 What does a switch do in a circuit? (a) makes electricity (b) opens or closes the loop (c) stores current (d) changes the voltage
8. 8.⚙️ Which actuator would you use to spin a robot’s wheels? (a) a pump (b) a servo motor (c) a motor (d) a buzzer
9. 9.🌐 In an IoT system, which part reads values, decides? (a) microcontroller (b) cloud server (c) actuator (d) Wi-Fi
10. 10.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) − (negative) (b) + (positive)
11. 11.True or false: a circle with V inside is the symbol for an ammeter. (a) False (b) True
12. 12.Which of these is a conductor? (a) a steel spoon (b) a paper strip (c) a plastic ruler (d) a dry cork
13. 13.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the output (b) the battery (c) the process (d) the input
14. 14.🔺 A current of 3 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
15. 15.What does a push button do? (a) springs back when let go (b) flips up or down (c) closes when tipped over (d) closes near a magnet
16. 16.🧩 Which component blows if current is high? (a) fuse (b) LED (c) thermistor (d) LDR
17. 17.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 54 Ω resistor? (a) yellow-green-black (b) green-yellow-brown (c) blue-yellow-black (d) green-yellow-black
18. 18.Which of these mainly makes sound? (a) a night lamp (b) an electric kettle (c) a ceiling fan (d) a siren
19. 19.Which of these usually has a microcontroller inside? (a) a plain wall switch (b) a toy robot (c) a candle (d) a spinning top
20. 20.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) both parts (b) neither part (c) the if part (d) the else part
21. 21.🤖 Does a smart watch usually have a microcontroller inside? (a) Yes (b) No
22. 22.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 8 hours. How many watt-hours (Wh) are saved?
23. 23.Which job is done by the USB port? (a) shows the board is on (b) brings power and code (c) runs the program (d) connect sensors and LEDs
24. 24.True or false: to throw cells in a fire is safe. (a) True (b) False
25. 25.🔋 8 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
26. 26.⚡ Which formula gives electric power? (a) P = V × I (b) P = V ÷ I (c) P = I ÷ V (d) P = V + I
27. 27.🧾 A family uses 30 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
28. 28.Which of these saves electricity? (a) use old filament bulbs (b) run fans in empty rooms (c) use LED lamps (d) leave the TV on standby
29. 29.⚙️ What is an actuator? (a) an output that acts (b) a program (c) a sensor (d) a battery
30. 30.🔍 A distance sensor sends a sound pulse and hears the echo 3 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
31. 31.🔘 Which kind of switch works only while pressed? (a) a push button (b) a slide switch (c) a tilt switch (d) a toggle switch
32. 32.📏 How many milliamperes (mA) is 0.84 A?
33. 33.True or false: “own switch for each bulb” is true of a series circuit. (a) True (b) False
34. 34.💡 In a series circuit, how many paths does the current have? (a) one (b) one for each bulb (c) two (d) none
35. 35.⚠️ Why must we never touch switches with wet hands? (a) it spoils the paint (b) water carries current (c) it is just untidy (d) water makes it cold
36. 36.🔁 What must there be for a current to flow? (a) a plastic gap (b) a broken path (c) one loose end (d) a complete loop
37. 37.🔁 total = 0
    for i = 1 to 5 { total = total + i }
    What is total at the end?
38. 38.📶 A pin set LOW gives about … (a) 1.5 V (b) 5 V (c) 9 V (d) 0 V
39. 39.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a cotton thread. Does the bulb glow? (a) No (b) Yes
40. 40.⚡ A device works on 12 V and takes 0.5 A. What is its power (in watts)? =

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