Final Answer:
The command used to read data from a physical device in Python is the open() function. This function is employed to open a file and return a corresponding file object that can be used to read data from the specified device.
Step-by-step explanation:
The open() function in Python is a built-in function that facilitates the opening of a file. When used with the appropriate file path and mode, such as 'r' for reading, it allows access to the contents of the specified physical device. For example, to read data from a text file named "example.txt" located on the desktop, the command would be file = open('C:/Users/Username/Desktop/example.txt', 'r'). The first argument is the file path, and the second argument is the mode, which is set to 'r' for reading.
Once the file is open, you can use various methods provided by the file object, such as read(), to retrieve the contents of the file. After completing the operations on the file, it's essential to close it using the close() method to free up system resources. Failing to close files properly may lead to issues like data corruption or loss.
In summary, the open() function, combined with the appropriate file path and mode, serves as the primary command to access and read data from a physical device in Python. This approach provides flexibility for working with different types of files, such as text files, CSV files, or other data sources.