# Class 11 NCERT Solutions- Chapter 5 Complex Numbers And Quadratic Equations – Exercise 5.1 | Set 2

### Question 11. 4-3i

Solution:

Let’s denote given number as a,

the complement of a =  =

= (4+3i)

Modulus of a = (|a|) = âˆš((4)2+(3)2)

|a|= âˆš(16+9)=âˆš(25)

|a| = 5

=

=

### Question 12. âˆš5+3i

Solution:

Let’s denote given number as a,

the complement of a =

= âˆš5-3i

Modulus of a (|a|) = âˆš((âˆš5)2+(-3)2)

|a|= âˆš(5+9)=âˆš(14)

|a|=âˆš(14)

### Question 13. -i

Solution:

Let’s denote given number as a,

the complement of a =

= i

Modulus of a (|a|) = âˆš((0)2+(-1)2)

|a|= âˆš(1)

|a|=1

= i

### Question 14.

Solution:

Let’s denote the given expression as z,

z =

z =

z =

As we know that (a+b)(a-b) = a2 – b2

z =

z =

z =

z =

z =

As we can write  = -i

z =

z = 0-

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