NCERT Class 12 Computer Science Computer Science: Chapter 1 — Exception Handling in Python
This chapter introduces exception handling in Python, a crucial aspect of writing robust programs. It explains that programs can encounter errors like syntax errors, runtime errors, or logical errors, leading to unexpected behavior. Python specifically uses exceptions to signal these runtime errors. The chapter details syntax errors, also known as parsing errors, which occur when the code violates the language's rules. These errors prevent program execution until corrected. The text illustrates how Python's interpreter reports syntax errors in both shell and script modes, providing descriptions and suggestions for rectification. Understanding and managing these errors is vital for effective Python programming and aligns with CBSE's curriculum for Class 12 Computer Science.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 12 |
| Subject | Computer Science |
| Book | Computer Science |
| Chapter | Chapter 1 — Exception Handling in Python |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 2 minutes |
| Word count | 351 |
Learning outcomes
- Understand the concept of exceptions in Python.
- Identify and differentiate between syntax errors and runtime errors.
- Recognize how Python reports syntax errors.
- Appreciate the importance of error handling in programming.
Vocabulary
| Word | Meaning |
|---|---|
| Elegant | Graceful and stylish in appearance or manner. |
| Efficient | Achieving maximum productivity with minimum wasted effort or expense. |
| Dependencies | A thing that is dependent on or conditioned by something else. |
| Articulated | Having or expressed in a clear and effective manner. |
| Optimal | Best or most favorable. |
| Unprincipled | Lacking moral principles; unconscionable. |
| Exceptions | A rule or circumstance that deviates from the general or usual case. |
| Syntax Errors | Errors detected when the rules of a programming language are not followed. |
| Interpreter | A program that directly executes instructions written in a programming language. |
| Parsing Errors | Another term for syntax errors. |
| Rectify | To correct something. |
| Shell mode | An interactive mode for executing Python commands one by one. |
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Practice questions
- What is the difference between a syntax error and a runtime error? Answer: Syntax errors occur when the code violates the programming language's rules and are detected by the interpreter before execution. Runtime errors occur during program execution, often due to unexpected conditions.
- What are syntax errors also known as? Answer: Syntax errors are also known as parsing errors.
- When are syntax errors detected? Answer: Syntax errors are detected when we have not followed the rules of the particular programming language while writing a program.
- What happens when a syntax error is encountered in shell mode? Answer: When a syntax error is encountered in shell mode, Python displays the name of the error and a small description about the error.
Practice MCQs
Q1. Which type of error is detected when the rules of a programming language are not followed?
Explanation: Syntax errors occur when the code does not adhere to the grammatical rules of the programming language.
Q2. Syntax errors are also known as:
Explanation: The text explicitly states that syntax errors are also known as parsing errors.
Q3. What does the Python interpreter do when it encounters a syntax error?
Explanation: The interpreter does not execute the program unless syntax errors are rectified.
Q4. In which mode does Python display the error name and a description when a syntax error occurs?
Explanation: The document mentions that in shell mode, Python displays the error name and a description.
Q5. According to Bjarne Stroustrup's quote, what is important for code maintenance?
Explanation: Bjarne Stroustrup emphasizes minimal dependencies to ease maintenance.
Frequently asked questions
What is exception handling in Python?
Exception handling in Python refers to the process of managing runtime errors (exceptions) that occur during program execution to prevent the program from crashing.
What are syntax errors in Python?
Syntax errors, also known as parsing errors, are mistakes in the code that violate the rules of the Python language. The interpreter detects these errors before the program runs.
When does a program execute unexpectedly?
A program can execute unexpectedly due to syntax errors, runtime errors, or logical errors in the code.
How does Python report a syntax error in shell mode?
In shell mode, Python displays the name of the syntax error and a brief description about it.
What is the role of the Python interpreter regarding syntax errors?
The Python interpreter detects syntax errors and prevents the program from executing until these errors are corrected.
Related resources
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Topics covered
NCERT Class 12 Computer Science — Computer Science — Chapter 1 — Exception Handling in Python. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.