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

A.

A signal that has only two states: HIGH and LOW

B.

A signal used exclusively for USB communication

C.

A discrete signal representing binary data

D.

A continuous signal that represents physical measurements

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 is always a sine wave

C.

It varies continuously over time

D.

It takes on infinite values within a range

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

A.

ATmega2560

B.

ATtiny85

C.

ESP8266

D.

ATmega328P

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

A.

20

B.

6

C.

10

D.

14

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

A.

8

B.

2

C.

6

D.

14

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

A.

Pins A0 and A1

B.

Pins 3 and 5

C.

Pins 0 (RX) and 1 (TX)

D.

Pins 11 and 12

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

A.

3.3V

B.

5V

C.

12V

D.

9V

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

A.

AREF

B.

Vin

C.

3.3V

D.

5V

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

A.

To convert continuous analog voltage into a digital number

B.

To convert digital code into analog voltage

C.

To amplify the current

D.

To reset the board

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 4095

C.

0 to 511

D.

0 to 255

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

A.

RX LED

B.

L (User LED)

C.

Power LED

D.

TX LED

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

A.

Phase Width Measurement

B.

Pin Wire Mode

C.

Power Wave Management

D.

Pulse Width Modulation

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

A.

AREF

B.

RESET

C.

IOREF

D.

GND

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

A.

1 A

B.

100 mA

C.

500 mA

D.

20 mA

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

A.

Crystal Oscillator

B.

Voltage Regulator

C.

Reset Button

D.

USB Controller

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

A.

1 GHz

B.

16 MHz

C.

8 MHz

D.

20 MHz

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

A.

Obstacles or motion via infrared light

B.

Sound waves

C.

Magnetic fields

D.

Humidity

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

A.

Potentiometer

B.

Op-Amp

C.

Photodiode

D.

IR LED

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

A.

Capacitor

B.

Photodiode

C.

IR LED

D.

Resistor

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

A.

To adjust the detection distance/sensitivity

B.

To turn the sensor on and off

C.

To change the emitted light color

D.

To regulate voltage to 3.3V

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.

NE555

B.

LM358 or LM393

C.

ATmega328

D.

7805

23 $What does LDR stand for?$

A.

Light Dependent Resistor

B.

Low Density Resistance

C.

Long Distance Resistor

D.

Light Detecting Relay

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

A.

Photoconductivity

B.

Photovoltaic effect

C.

Hall effect

D.

Piezoelectric effect

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

A.

Resistance becomes zero instantly

B.

Resistance remains constant

C.

Resistance increases as light intensity increases

D.

Resistance decreases as light intensity increases

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

A.

Copper

B.

Aluminum

C.

Silicon

D.

Cadmium Sulfide (CdS)

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 becomes negative

C.

The voltage decreases

D.

The voltage increases

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

A.

A few ohms

B.

Negative resistance

C.

Zero ohms

D.

Several Mega-ohms

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

A.

Ultrasonic Sensor (HC-SR04)

B.

DHT11

C.

PIR Sensor

D.

LDR

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

A.

1 kHz

B.

20 Hz

C.

1 MHz

D.

40 kHz

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 adjusts the sensitivity

B.

It emits the sound wave

C.

It provides the 5V power

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.

~10 microseconds

D.

~100 microseconds

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

A.

It requires a magnet to work

B.

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

C.

It only works in a vacuum

D.

It cannot measure in the dark

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

A.

No, sound waves require a medium to travel

B.

Only if the object is metal

C.

Yes, perfectly

D.

Yes, but with reduced range

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.

DHT11

B.

DHT22

C.

Neither works with Arduino

D.

Both are identical

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

A.

SPI Protocol

B.

Continuous Analog Voltage

C.

Single-wire Digital Signal

D.

I2C Protocol

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

A.

1 second

B.

1 millisecond

C.

10 seconds

D.

1 microsecond

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

A.

Photodiode

B.

Strain gauge

C.

Capacitive humidity sensor

D.

Piezo element

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

A.

Shunt resistor

B.

Pull-down resistor

C.

Pull-up resistor

D.

Current limiting resistor

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

A.

-50°C to 150°C

B.

0°C to 50°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.

DHT.h

B.

SPI.h

C.

LiquidCrystal.h

D.

Servo.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.

digitalRead(A0)

D.

analogRead(A0)

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

A.

Integer (0 to 1023)

B.

String ("ON" or "OFF")

C.

Float (0.0 to 5.0)

D.

Integer (HIGH or LOW)

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

A.

pinMode()

B.

setupPin()

C.

configIO()

D.

digitalWrite()

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

A.

The board resets

B.

The pin burns out

C.

analogRead() returns 0

D.

analogRead() returns 1023

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

A.

Generating PWM signals

B.

Reading analog voltages

C.

Writing to EEPROM

D.

Serial communication

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

A.

8-bit (0-255)

B.

10-bit (0-1023)

C.

12-bit (0-4095)

D.

16-bit (0-65535)

Unit 2 - Practice Quiz