Final answer:
An unhandled exception causes a program to terminate and provides a traceback with details of the exception. Using try/except blocks can prevent a crash and allow for user-friendly error handling or corrective actions.
Step-by-step explanation:
If an exception is raised in a program and it is not handled with a try/except statement, the program will abruptly terminate, or 'crash'. When an exception is unhandled, the Python interpreter stops executing the program and typically prints an error message along with a traceback to the console. This traceback will contain information about where the exception occurred and the type of exception that was raised, which helps in diagnosing the problem in the code. It's important to use try/except blocks in programs to handle potential exceptions. This prevents the program from crashing and allows the developer to provide users with a more friendly error message, or to take corrective action when an exception occurs.