**Download NCERT Solutions for Class 8 Maths Chapter 12 Exercise 12.2 – Exponents and Powers**

**NCERT Solutions for Class 8 Maths ****Chapter 12 Exercise 12.2 – Exponents and Powers****, has been designed by the NCERT to test the knowledge of the student on the topic – ****Use of Exponents to Express Small Numbers in Standard Form – Comparing very large and very small numbers**

**1. Express the following numbers in standard form.**

**i) 0000000000085
**

**– 0.0000000000085 = 8.5 × 10**

__Sol.:__^{-12}

**ii) 0.00000000000942
**

**– 0.00000000000942 = 9.42 × 10**

__Sol.:__^{-12}

**iii) 6020000000000000
**

**– 6020000000000000 = 6.02 × 10**

__Sol.:__^{15}

**iv) 00000000837
**

**– 0.00000000837 = 8.37 × 10**

__Sol.:__^{-9}

**v) 31860000000
**

**– 31860000000 = 3.186 × 10**

__Sol.:__^{10}

**2. Express the following numbers in usual form.**

**i. 3.02 × 10 ^{-6
}**

**– 3.02 × 10**

__Sol.:__^{-6}= 3.02 × = 0.00000302

**ii. 4.****5 × 10 ^{4
}**

**– 4.5 × 10**

__Sol.:__^{4}= 4.5 × 10000 = 45000

**iii. 3 × 10 ^{-8
}**

**– 3 × 10**

__Sol.:__^{-8}= 3 × = 0.00000003

**iv. 1.****0001 × 10 ^{9
}**

**– 1.0001 × 10**

__Sol.:__^{9}= 1000100000

**v. 5.8 × 10 ^{12
}**

**– 5.8 × 10**

__Sol.:__^{12}= 5.8 × 1000000000000 = 5800000000000

**vi. 3.61492 × 10 ^{6
}**

**– 3.61492 × 10**

__Sol.:__^{6}= 3.61492 × 1000000 = 3614920

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

**i) 1 micron is equal to .
**

**– 1 micron = 1 × 10**

__Sol.:__^{-6}m

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

**– Charge of one electron = 1.6 × 10**

__Sol.:__^{-19}coulomb

**iii) Size of a bacteria is 0.0000005 m
**

**– Size of a bacteria = 5 × 10**

__Sol.:__^{-7}m

**iv) Size of a plant cell is 0.00001275 m
**

**– Size of a plant cell = 1.275 × 10**

__Sol.:__^{-5}m

**v) Thickness of a thick paper is 0.07 mm
**

**– Thickness of a thick paper = 7 × 10**

__Sol.:__^{-2}mm

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

**Sol.: **– Thickness of the stack = Thickness of 5 book + Thickness of 5 Paper Sheet

= 5 × 20 + 5 × 0.016

= 100 + 0.08

= 100.08 mm

= 1.0008 × 10

^{2}mm

**The next Exercise for** **NCERT Solutions for Class 8 Maths Chapter 13 Exercise 13.1 – Direct and Inverse Proportions**** ****can be accessed by clicking here**

**Download NCERT Solutions for Class 8 Maths Chapter 12 Exercise 12.2 – Exponents and Powers**

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