Raspberry Pi and LDR Sensor

What is the working principle of an LDR sensor?

• The sensor emits light to detect objects.

• The sensor measures the temperature of the environment.

• The sensor detects sound waves and converts them into electrical signals.

• The resistance of the sensor changes with the amount of light falling on it.

Name one component required for an automatic streetlight project.

• temperature sensor

• light sensor

• motion sensor

• sound sensor

What is the code for reading LDR sensor data in Raspberry Pi?

• import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BCM) GPIO.setup(17, GPIO.IN) sensor_value = GPIO.input(17) GPIO.cleanup()

• import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BCM) GPIO.setup(22, GPIO.IN) sensor_value = GPIO.input(22) GPIO.cleanup()

• import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BCM) GPIO.setup(27, GPIO.IN) sensor_value = GPIO.input(27) GPIO.cleanup()

• import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BCM) GPIO.setup(18, GPIO.IN) sensor_value = GPIO.input(18) GPIO.cleanup()

How can you control an LED using Raspberry Pi?

• Connect the LED to a USB port and use a software to control its state.

• Connect the LED to a GPIO pin and write a Python script to control the pin's state.

• Connect the LED to the power supply directly and use a software to control its state.

• Connect the LED to the HDMI port and use a software to control its state.

What happens to the resistance of an LDR sensor when exposed to light?

• The resistance decreases.

• The resistance fluctuates.

• The resistance increases.

• The resistance remains the same.

What is the purpose of an LDR sensor in an automatic streetlight project?

• To detect ambient light levels and control the streetlights

• To measure temperature and humidity levels

• To detect motion and activate the streetlights

• To monitor air pollution levels

Name another component required for an automatic streetlight project.

• light sensor

• temperature sensor

• motion sensor

• timer

What is the code for turning on an LED in Raspberry Pi?

• JavaScript code using GPIO library

• Python code using GPIO library

• C++ code using GPIO library

• Java code using GPIO library

What is the code for turning off an LED in Raspberry Pi?

• GPIO.output(pin_number, 0)

• GPIO.output(pin_number, GPIO.LOW)

• GPIO.output(pin_number, GPIO.OFF)

• GPIO.output(pin_number, GPIO.HIGH)

How does an LDR sensor detect light?

• By emitting light and measuring the reflection

• By detecting the change in temperature

• By measuring the change in resistance

• By measuring the change in voltage