 # Class 11 Computer Science Ch 7 Python Fundamental – Check Point 7.4 Sumita Arora Solution

## Class 11 Computer Science – Ch 7: Python Fundamental

### Check Point 7.4

Sumita Arora Book Exercise Solution

#### 1.  What is a variable?

Answer: A variable is a named location that refers to a value and whose values can be used and processed during the run.

#### 2.  Why is a variable called a symbolic variable?

Answer: In Python, Variables are known as Symbolic variables, because these are used as named labels.

#### 3. Create variables for the following:

(i) to hold train number
(ii) to hold the name of a subject
(iii) to hold balance amount in a bank account
(iv) to hold a phone number

(ii) subName = “Informatics Practices”

(iii) balanceAmount = 25698.36

(iv) phoneNumber = ‘+91 9541 954 258’

#### 4.  What do you mean by dynamic typing of a variable? What is the caution you must take care of?

Answer: In Python, a variable pointing to a value of a certain type, can be made to point to a value of different type, called Dynamic Typing.

Example:         x = 2569                          # x pointing integer

x = 25698.398                 # now x  pointing float

x = “anjeevsinghacademy.com”     # x pointing a string

Caution with Dynamic Typing

Need to ensure that variables with right type of values should be used in expressions.

#### 5.  What happens when you try to access the value of an undefined variable?

Answer: Accessing the value of an undefined variable, will show an error called Name Error.

In Python, a variable is defined only when we assign some value to it.

#### 6.  What is wrong with the following statement?

Number = input (“Number”)

Sqr = Number*Number

Number = input (“Number”)

input() function in Python return a string value. So Number is a String data type.

Sqr = Number*Number

Because Number is string, so we cannot perform the multiplication operation with Number.

#### 7.  Write Python code to obtain the balance amount.

amount = float(input(“Enter Amount :”))
expense = float(input(“Enter Expense :”))
balance_amount = amount – expense
print(“Balance Amount :”, balance_amount)