NCERT Solutions for Class 8 Maths Chapter 12 (Ex 12.2) Exponents and Powers

NCERT Solutions for Class 8 Chapter 12 Exponents and Powers -Free PDF Download

Free PDF download of NCERT Solutions Maths Class 8 Solutions Chapter 12 – Exponents and Powers solved by Expert Maths Teachers on CoolGyan.Org. All Chapter 12 – Exponents and Powers Questions with Solutions for NCERT to help you to revise complete Syllabus and Score More marks.
Maths Revision Notes for Class 8

Chapter NameExponents and Powers
ChapterChapter 12
ExerciseExercise 12.2
ClassClass 8
SubjectMaths NCERT Solutions
BoardCBSE
TEXTBOOKCBSE NCERT
CategoryNCERT Solutions

NCERT SOLVED

1. Express the following numbers in standard form:

(i) 0.0000000000085

(ii) 0.00000000000942

(iii) 6020000000000000

(iv) 0.00000000837

(v) 31860000000

Ans. (i) 0.0000000000085

= 0.0000000000085   = 

(ii) 0.00000000000942

= 0.00000000000942   =

(iii) 6020000000000000

= 6020000000000000   = 

(iv) 0.00000000837

= 0.00000000837   = 

(v) 31860000000

= 31860000000   = 

2. Express the following numbers in usual form:

(i) 

(ii) 

(iii) 

(iv) 

(v) 

(vi) 

Ans. (i) 

(ii) 4.5  10000 = 45000

(iii)  = 0.00000003

(iv)  = 1000100000

(v)  = 5.8 x 1000000000000

= 5800000000000

(vi)  = 3.61492  1000000

= 3614920

3. Express the number appearing in the following statements in standard form:

(i)1 micron is equal to  m.

(ii) Charge of an electron is 0.000,000,000,000,000,000,16 coulomb.

(iii) Size of a bacteria is 0.0000005 m.

(iv) Size of a plant cell is

0.00001275 m.

(v) Thickness if a thick paper is 0.07 mm.

Ans. (i) 1 micron

=  m

(ii)Charge of an electron is

0.00000000000000000016 coulombs.

=0.00000000000000000016×101910190.00000000000000000016×10191019

=  coulomb

(iii) Size of bacteria = 0.0000005

510000000=5107=5×10−7510000000=5107=5×10−7 m

(iv) Size of a plant cell is 0.00001275 m

= 0.00001275   =  m

(v) Thickness of a thick paper = 0.07 mm

= mm =  mm

4. In a stack there are 5 books each of thickness 20 mm and 5 paper sheets each of thickness 0.016 mm. What is the total thickness of the stack?

Ans. Thickness of one book = 20 mm

Thickness of 5 books = 20  5 = 100 mm

Thickness of one paper = 0.016 mm

Thickness of 5 papers = 0.016  5

= 0.08 mm

Total thickness of a stack = 100 + 0.08

=100.08 mm

= 100.08 

 mm