## Class 11 Computer Science – Ch 8: Data Handling

### Check Point 8.2

**Sumita Arora Book Exercise Solution**

##### 1. What are floating point numbers? When are they preferred over integers?

**Answer: **Numbers having decimal points i.e. numbers written in a faction called Floating point numbers. Example: 5.2, 0.5698, 45698.3699895

The floating point number is required when you want to do calculations related to accounting and calculation needs accuracy.

##### 2. What are complex numbers? How would Python represent a complex number with a real part as 3 and an imaginary part as 2.5?

**Answer: **A Complex number is in the form A + B i where i is the imaginary number equal to the square root of -1. Python represents complex numbers in the form of A + B j. That is to represent an imaginary number,

Python used j in place of traditional i. Python represents complex numbers as a pair of floating point numbers.

To represent a complex number with a real part as 3 and an imaginary part as 2.5 –

**com_num = 3 + 2.5 j**

##### 3. What will be the output of following

p = 3j

q = p + ( 1 + 1.5j )

print (p)

print (q)

**Answer: ** Output is :

3j

1 + 4.5j

**Reason:** p is a complex number which having only imaginary part. (1 + 1.5j) is a complex number having real part is 1 and imaginary part is 1.5j. So when you are doing arithmetic with complex number, it adds real part with real and imaginary part with imaginary.

That’s why the **value of q is 1 + 4.5j**

##### 4. What will be the output of following

r = 2.5 + 3.9j

print (r . real)

print (r . imag)

**Answer: **Output :

2.5

3.9

##### 5. Why does Python uses the symbol j to represent the imaginary part of a complex number instead of the conventional i ?

**Answer: **In the Electrical engineering, i is used to represent the current and they use the symbol j for the square root of -1. So for their simplicity, Python adheres to this convention.