ECE249 Unit 2: Introduction of Arduino and Sensors - MCQ Practice | B. Tech. CSE

1 $Which of the following statements best describes an Analog Signal ?$

A.

A signal that has only two states: HIGH and LOW

B.

A continuous signal that represents physical measurements

C.

A discrete signal representing binary data

D.

A signal used exclusively for USB communication

2 $What is the primary characteristic of a Digital Signal ?$

A.

It represents data as a sequence of discrete values (0s and 1s)

B.

It takes on infinite values within a range

C.

It varies continuously over time

D.

It is always a sine wave

3 $Which microcontroller is used on the standard Arduino Uno R3 board?$

A.

ATmega328P

B.

ATtiny85

C.

ATmega2560

D.

ESP8266

4 $How many digital I/O pins are available on the Arduino Uno board?$

A.

6

B.

10

C.

14

D.

20

5 $How many of the digital pins on the Arduino Uno provide PWM (Pulse Width Modulation) output?$

A.

14

B.

2

C.

8

D.

6

6 $Which pins on the Arduino Uno are used for UART serial communication ?$

A.

Pins 0 (RX) and 1 (TX)

B.

Pins 11 and 12

C.

Pins 3 and 5

D.

Pins A0 and A1

7 $What is the operating voltage of the ATmega328P on a standard Arduino Uno?$

A.

5V

B.

3.3V

C.

9V

D.

12V

8 $Which pin allows you to supply an external voltage to the Arduino board (typically 7-12V)?$

A.

Vin

B.

AREF

C.

3.3V

D.

5V

9 $What is the function of the ADC (Analog-to-Digital Converter) in the Arduino?$

A.

To reset the board

B.

To amplify the current

C.

To convert continuous analog voltage into a digital number

D.

To convert digital code into analog voltage

10 $The Arduino Uno has a 10-bit ADC . What is the range of digital values it can produce?$

A.

0 to 1023

B.

0 to 255

C.

0 to 4095

D.

0 to 511

11 $Which built-in LED is connected to digital pin 13 on the Arduino Uno?$

A.

Power LED

B.

L (User LED)

C.

RX LED

D.

TX LED

12 $What does PWM stand for in the context of Arduino pins?$

A.

Pin Wire Mode

B.

Pulse Width Modulation

C.

Power Wave Management

D.

Phase Width Measurement

13 $Which Arduino pin is used to set the reference voltage for analog inputs?$

A.

AREF

B.

IOREF

C.

GND

D.

RESET

14 $What is the recommended maximum DC current per I/O pin on the Arduino Uno?$

A.

500 mA

B.

100 mA

C.

20 mA

D.

1 A

15 $Which component on the Arduino board ensures the voltage does not exceed 5V when powered via the DC jack?$

A.

Voltage Regulator

B.

Crystal Oscillator

C.

Reset Button

D.

USB Controller

16 $What is the frequency of the crystal oscillator on the Arduino Uno?$

A.

16 MHz

B.

20 MHz

C.

8 MHz

D.

1 GHz

17 $What is an IR Sensor primarily used to detect?$

A.

Sound waves

B.

Magnetic fields

C.

Humidity

D.

Obstacles or motion via infrared light

18 $Which component acts as the transmitter in an IR sensor module?$

A.

Op-Amp

B.

Potentiometer

C.

Photodiode

D.

IR LED

19 $Which component acts as the receiver in an active IR sensor module?$

A.

Resistor

B.

IR LED

C.

Capacitor

D.

Photodiode

20 $What is the function of the potentiometer on a digital IR obstacle avoidance sensor module?$

A.

To change the emitted light color

B.

To regulate voltage to 3.3V

C.

To turn the sensor on and off

D.

To adjust the detection distance/sensitivity

21 $Why can humans generally not see the light emitted by an IR sensor?$

A.

It is too bright

B.

It is blocked by the air

C.

It is too dim

D.

Its wavelength is outside the visible spectrum

22 $Which component is often used as a comparator in IR sensor modules to provide a digital output?$

A.

7805

B.

NE555

C.

LM358 or LM393

D.

ATmega328

23 $What does LDR stand for?$

A.

Light Detecting Relay

B.

Light Dependent Resistor

C.

Low Density Resistance

D.

Long Distance Resistor

24 $What is the working principle of an LDR?$

A.

Hall effect

B.

Photovoltaic effect

C.

Piezoelectric effect

D.

Photoconductivity

25 $How does the resistance of an LDR change with light intensity?$

A.

Resistance remains constant

B.

Resistance becomes zero instantly

C.

Resistance decreases as light intensity increases

D.

Resistance increases as light intensity increases

26 $Which material is commonly used to manufacture LDRs?$

A.

Copper

B.

Cadmium Sulfide (CdS)

C.

Aluminum

D.

Silicon

27 $In a voltage divider circuit with a fixed resistor and an LDR, if the LDR is connected to ground, what happens to the output voltage when light intensity increases?$

A.

The voltage stays at 5V

B.

The voltage decreases

C.

The voltage becomes negative

D.

The voltage increases

28 $What is the typical resistance of an LDR in total darkness?$

A.

Negative resistance

B.

Several Mega-ohms

C.

A few ohms

D.

Zero ohms

29 $Which sensor is commonly used to measure distance using sound waves?$

A.

LDR

B.

DHT11

C.

PIR Sensor

D.

Ultrasonic Sensor (HC-SR04)

30 $What is the typical frequency of the sound waves emitted by the HC-SR04 ultrasonic sensor?$

A.

40 kHz

B.

20 Hz

C.

1 kHz

D.

1 MHz

31 $What is the function of the Trig (Trigger) pin on the HC-SR04 sensor?$

A.

It receives the reflected sound wave

B.

It connects to Ground

C.

It initiates the measurement by sending a pulse

D.

It powers the sensor

32 $What is the function of the Echo pin on the HC-SR04 sensor?$

A.

It provides the 5V power

B.

It adjusts the sensitivity

C.

It emits the sound wave

D.

It outputs a high pulse with duration proportional to the distance

33 $The formula to calculate distance () using an ultrasonic sensor, where is the echo time and is the speed of sound, is:$

A.

B.

C.

D.

34 $If the speed of sound is approximately 340 m/s, how many microseconds does it take to travel 1 cm (there and back)?$

A.

~29 microseconds

B.

~58 microseconds

C.

~100 microseconds

D.

~10 microseconds

35 $What is a limitation of the ultrasonic sensor?$

A.

It cannot measure in the dark

B.

It requires a magnet to work

C.

It has a 'blind zone' very close to the sensor (e.g., < 2cm)

D.

It only works in a vacuum

36 $Can an ultrasonic sensor work in a vacuum?$

A.

No, sound waves require a medium to travel

B.

Yes, but with reduced range

C.

Yes, perfectly

D.

Only if the object is metal

37 $What do the DHT11 and DHT22 sensors measure?$

A.

Pressure and Altitude

B.

Temperature and Humidity

C.

Distance and Time

D.

Light and Color

38 $Between DHT11 and DHT22, which one generally provides higher accuracy and a wider range?$

A.

DHT22

B.

DHT11

C.

Neither works with Arduino

D.

Both are identical

39 $What type of data signal does the DHT11 sensor output?$

A.

Continuous Analog Voltage

B.

I2C Protocol

C.

Single-wire Digital Signal

D.

SPI Protocol

40 $What is the typical sampling interval (minimum time between readings) for a DHT11 sensor?$

A.

1 second

B.

10 seconds

C.

1 millisecond

D.

1 microsecond

41 $Which sensing element is used inside a DHT sensor to measure moisture?$

A.

Capacitive humidity sensor

B.

Photodiode

C.

Piezo element

D.

Strain gauge

42 $When wiring a DHT sensor, a resistor is often placed between VCC and the Data pin. What is this resistor called?$

A.

Pull-up resistor

B.

Current limiting resistor

C.

Shunt resistor

D.

Pull-down resistor

43 $The temperature range of the DHT11 is approximately:$

A.

0°C to 50°C

B.

-50°C to 150°C

C.

Absolute Zero

D.

100°C to 200°C

44 $To read data from a DHT11 using Arduino, which library is commonly used?$

A.

LiquidCrystal.h

B.

SPI.h

C.

Servo.h

D.

DHT.h

45 $If an analog sensor is connected to pin A0, which Arduino function is used to read the value?$

A.

Serial.read(A0)

B.

analogWrite(A0)

C.

analogRead(A0)

D.

digitalRead(A0)

46 $What is the return type and range of the digitalRead() function?$

A.

Integer (HIGH or LOW)

B.

Integer (0 to 1023)

C.

Float (0.0 to 5.0)

D.

String ("ON" or "OFF")

47 $Which Arduino function is used to configure a pin as an Input or Output?$

A.

setupPin()

B.

digitalWrite()

C.

pinMode()

D.

configIO()

48 $What happens if you supply 5V to an Analog Input pin on Arduino?$

A.

The board resets

B.

analogRead() returns 0

C.

The pin burns out

D.

analogRead() returns 1023

49 $The command analogWrite() is used for which specific functionality?$

A.

Writing to EEPROM

B.

Generating PWM signals

C.

Serial communication

D.

Reading analog voltages

50 $What is the resolution of the analogWrite() function (PWM resolution) on an Arduino Uno?$

A.

8-bit (0-255)

B.

12-bit (0-4095)

C.

10-bit (0-1023)

D.

16-bit (0-65535)

Unit 2: Introduction of Arduino and Sensors - Practice Quiz

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