15 extra multiple-choice questions for Python -Variables and Operators (12th Standard Computer Science, Samacheer Kalvi), beyond the ones printed in the textbook — each with the correct option highlighted and a clear, worked explanation. Free to read in English and Tamil.
Q1
Which of the following is an invalid identifier in Python because it contains an illegal punctuation character?
- A. total_marks
- B. num1
- C. name\$Correct
- D. _Sum
Explanation. According to Python identifier rules, punctuation characters such as % or \$ are not allowed inside identifiers.
Q2
In Python, which of the following operators is used for performing floor division?
- A. /
- B. %
- C. //Correct
- D. **
Explanation. The floor division operator (//) performs integer division and returns the quotient as an integer value after discarding the fractional part.
Q3
Which built-in function is used to explicitly convert a string input containing a numerical value into an integer in Python?
- A. str()
- B. float()
- C. int()Correct
- D. input()
Explanation. The int() function is used to convert string data representing a number into integer data explicitly, since the input() function accepts all data as strings by default.
Q4
How does the Python interpreter treat lines that begin with the hash symbol (#)?
- A. They are executed as high-priority commands.
- B. They are treated as comments and ignored by the interpreter.Correct
- C. They are used to define block structures instead of indentation.
- D. They are flagged as syntax errors during execution.
Explanation. In Python, comments begin with the hash symbol (#) and are ignored by the interpreter during execution.
Q5
In Python, what character sequence is used to enclose multiline comments?
- A. //
- B. #
- C. ''' (triple quotes)Correct
- D. /* and */
Explanation. Multiline comments in Python should be enclosed within a set of triple quotes (''' ''').
Q6
Which of the following escape sequences is used to represent a carriage return in Python strings?
- A. \\n
- B. \\t
- C. \\rCorrect
- D. \\\\
Explanation. In Python strings, the escape sequence '\r' represents a carriage return, while '\n' is for newline and '\t' is for tab.
Q7
Which number representation is denoted by prefixing an integer with the digit 0 followed by the letter 'o' (such as 0o102) in Python?
- A. Binary integer
- B. Octal integerCorrect
- C. Hexadecimal integer
- D. Long decimal integer
Explanation. In Python, octal integers are represented by using the digit 0 followed by the lowercase letter 'o'.
Q8
What is the correct syntax for the conditional (ternary) operator in Python?
- A. Variable Name = [Test expression] ? [on_true] : [on_false]
- B. Variable Name = [on_true] if [Test expression] else [on_false]Correct
- C. Variable Name = if [Test expression] then [on_true] else [on_false]
- D. Variable Name = [on_true] else [on_false] if [Test expression]
Explanation. The conditional (ternary) operator syntax in Python is: Variable Name = [on_true] if [Test expression] else [on_false].
Q9
Given the variable values a = 97 and b = 35, what will be the result of the logical expression: not a > b in Python?
- A. True
- B. FalseCorrect
- C. None
- D. SyntaxError
Explanation. Since a (97) is greater than b (35), the expression a > b evaluates to True. Applying the 'not' operator negates True to False.
Q10
Python identifiers are case-sensitive. Which of the following is true regarding two identifiers named Sum and sum?
- A. They are treated as identical by the interpreter.
- B. They are recognized as two distinct, different identifiers.Correct
- C. They will cause a compilation error if used in the same program.
- D. The interpreter automatically converts Sum to lowercase sum.
Explanation. Python identifiers are case-sensitive, meaning that uppercase and lowercase letters are treated as distinct, so Sum and sum are different identifiers.
Q11
Which of the following is a valid example of exponent data representation for floating-point numbers in Python?
- A. 12.E04Correct
- B. 12L
- C. 0o12
- D. 0X12
Explanation. In Python, floating-point exponent data contains a decimal digit part, a decimal point, and an exponent part followed by one or more digits, such as 12.E04.
Q12
Which of the following characters is NOT used as a delimiter in Python expressions, lists, dictionaries, or strings?
- A. :
- B. ;
- C. \$Correct
- D. ,
Explanation. In Python, delimiters include characters like parentheses, brackets, braces, commas, colons, and semicolons, but symbols like '\$' are not used as delimiters.
Q13
When using Python IDLE in interactive mode, what will be the output of evaluating the expression 5 ** 2?
- A. 10
- B. 25Correct
- C. 2.5
- D. 50
Explanation. The double asterisk (**) is the exponentiation operator in Python, so evaluating 5 ** 2 yields 25.
Q14
Which of the following characters can a Python identifier legally begin with?
- A. Only lowercase alphabets
- B. Only uppercase alphabets
- C. An alphabet (A..Z or a..z) or an underscore (_)Correct
- D. Any alphanumeric character including digits
Explanation. A Python identifier must start with either an alphabet letter (A..Z or a..z) or an underscore (_).
Q15
If the initial value of x is 10, what will be the value of x after executing the compound assignment statement x += 20?
- A. 10
- B. 20
- C. 30Correct
- D. 200
Explanation. The statement x += 20 is equivalent to x = x + 20, which adds 20 to the initial value of 10, resulting in 30.
