MCQs on Exception Handling | Python programming

1. Introduction to Exceptions

1. What is an exception in Python?
   • a) A bug that occurs in the code
   • b) An event that disrupts the normal flow of the program
   • c) A special type of variable
   • d) A syntax error
2. What happens when an exception is raised in Python?
   • a) The program stops running immediately
   • b) The program runs indefinitely
   • c) The program skips to the next statement
   • d) The program catches the exception and continues
3. Which of the following is an example of an exception in Python?
   • a) IndexError
   • b) undefined_variable
   • c) out_of_memory
   • d) InfiniteLoop
4. Which of the following Python errors indicates that you are trying to divide a number by zero?
   • a) ValueError
   • b) TypeError
   • c) ZeroDivisionError
   • d) IndexError
5. How does Python handle exceptions?
   • a) By terminating the program
   • b) By printing the exception message and continuing
   • c) By ignoring the exception
   • d) By suspending the program

2. Try, Except, Else, Finally Blocks

6. What is the purpose of the try block in Python?
   • a) To test the code for exceptions
   • b) To execute code that is always successful
   • c) To handle the exception if it occurs
   • d) To specify the return value of a function
7. Which block is executed when no exception occurs in the try block?
   • a) except
   • b) else
   • c) finally
   • d) raise
8. What will happen if an exception is raised in the try block and there is no except block to catch it?
   • a) Python will stop the program
   • b) The program will continue to run after printing the error message
   • c) The exception is ignored
   • d) Python will ask the user for input
9. What is the role of the finally block in exception handling?
   • a) It runs if no exception occurs
   • b) It runs if an exception occurs
   • c) It always runs, regardless of whether an exception occurs or not
   • d) It only runs if the exception is caught
10. Which of the following is the correct syntax for using try, except, else, and finally?
    • a) try: code except: code else: code finally: code
    • b) try: code except: code else: code
    • c) try: code except: code finally: code
    • d) try: code except: code

3. Custom Exceptions

11. How do you define a custom exception in Python?
    • a) By creating a function
    • b) By subclassing the built-in Exception class
    • c) By using the raise keyword
    • d) By calling Exception("Custom message")
12. Which of the following is the correct way to define a custom exception?
    • a) class MyException: pass
    • b) class MyException(Exception): pass
    • c) class MyException(BaseException): pass
    • d) class MyException(Exception) { pass }
13. How can you raise a custom exception in Python?
    • a) raise MyException()
    • b) raise Exception()
    • c) throw MyException()
    • d) trigger MyException()
14. What is the correct way to handle a custom exception in a try-except block?
    • a) except MyException:
    • b) except MyException()
    • c) catch MyException
    • d) except MyException as e
15. In the following code, what is the purpose of raise?
    if condition: raise ValueError("A custom error occurred")
    • a) It terminates the program
    • b) It throws an exception
    • c) It skips the condition
    • d) It prints an error message

4. Raising Exceptions

16. Which of the following is the correct syntax for raising an exception?
    • a) throw Exception()
    • b) raise Exception()
    • c) raise Error()
    • d) signal Exception()
17. What happens if you raise an exception inside a try block?
    • a) The program continues to the next statement
    • b) The program terminates immediately
    • c) The exception is passed to the except block for handling
    • d) The finally block is skipped
18. How can you raise a custom exception with a specific message in Python?
    • a) raise Exception("Custom message")
    • b) throw Exception("Custom message")
    • c) raise ValueError("Custom message")
    • d) signal Exception("Custom message")
19. Which of the following statements raises an exception intentionally when a condition is met?
    • a) if x < 10: raise Exception("x is too small")
    • b) if x < 10: raise ValueError("x is too small")
    • c) if x < 10: raise MyException("x is too small")
    • d) All of the above
20. Can a function raise an exception to be handled by a calling function?
    • a) No, only the calling function can raise an exception
    • b) Yes, a function can raise an exception
    • c) Only built-in exceptions can be raised
    • d) No, exceptions can only be raised in the global scope

5. Assertions

21. What is the purpose of assertions in Python?
    • a) To check if a condition is true and raise an exception if it is false
    • b) To handle all exceptions automatically
    • c) To define custom exceptions
    • d) To raise an exception in a try block
22. Which function is used for assertion in Python?
    • a) assert()
    • b) assertEqual()
    • c) check()
    • d) assertTrue()
23. What happens if an assertion fails in Python?
    • a) The program continues running normally
    • b) An AssertionError is raised
    • c) The program terminates immediately without any message
    • d) A custom exception is raised
24. Which of the following is an example of a correct assertion statement in Python?
    • a) assert x == 10
    • b) assert(x == 10)
    • c) assert 10 == x
    • d) assert (x == 10)
25. What is the correct behavior when running Python in optimized mode (using python -O) regarding assertions?
    • a) Assertions are executed normally
    • b) Assertions are ignored
    • c) Assertions are automatically handled by Python
    • d) Assertions are logged into a file
26. What is the output if the following code executes successfully?
    x = 5 assert x > 3, "x is less than or equal to 3"
    • a) “x is less than or equal to 3”
    • b) No output, execution continues
    • c) AssertionError is raised
    • d) “x is greater than 3”
27. Can assertions be used to catch exceptions raised by code?
    • a) Yes, they are useful for handling errors
    • b) No, they are used for debugging purposes
    • c) Yes, they can raise custom exceptions
    • d) No, assertions only check conditions
28. Which of the following is a valid assertion with a message?
    • a) assert condition, "Error message"
    • b) assert "Error message" condition
    • c) assert condition then "Error message"
    • d) assert condition message="Error"
29. What happens when an assertion statement is included in production code?
    • a) It has no effect
    • b) It slows down the performance
    • c) It checks the condition and raises an error if it fails
    • d) It always raises an exception
30. In which scenarios would you typically use assertions in Python?
    • a) To validate function arguments during development
    • b) To handle runtime exceptions
    • c) To enforce business logic in production code
    • d) To replace try-except blocks

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