# NCERT Solutions for Class 8 Maths Maths - NCERT Solution Chapter 12

## Exponents and Powers Class 8

### Exercise 12.1 : Solutions of Questions on Page Number : 197

Q1 :

Evaluate

(i) 3 - 2 (ii) ( - 4) - 2 (iii)

(i)

(ii)

(iii)

Q2 :

Simplify and express the result in power notation with positive exponent.

(i) (ii)

(iii) (iv)

(v)

(i) ( - 4)5 ÃƒÂ· ( - 4)8 = ( - 4)5 - 8 (am ÃƒÂ· an = am - n)

= ( - 4) - 3

(ii)

(iii)

(iv) (3 - 7 ÃƒÂ· 3 - 10) × 3 - 5 = (3 - 7 - ( - 10)) × 3 - 5 (am ÃƒÂ· an = am - n)

= 33 × 3 - 5

= 33 + ( - 5) (am × an = am + n)

= 3 - 2

(v) 2 - 3 × ( - 7) - 3 =

Q3 :

Find the value of.

(i) (30 + 4 - 1) × 22 (ii) (2 - 1 × 4 - 1) ÃƒÂ·2 - 2

(iii) (iv) (3 - 1 + 4 - 1 + 5 - 1)0

(v)

Q4 :

Evaluate (i) (ii)

Q5 :

Find the value of m for which 5m ÃƒÂ·5-3 = 55.

Q6 :

Evaluate (i) (ii)

Q7 :

Simplify. (i) (ii)

### Exercise 12.2 : Solutions of Questions on Page Number : 200

Q1 :

Express the following numbers in standard form.

(i) 0.0000000000085 (ii) 0.00000000000942

(iii) 6020000000000000 (iv) 0.00000000837

(v) 31860000000

Q2 :

Express the following numbers in usual form.

(i) 3.02 x 10-6 (ii) 4.5 x 104

(iii) 3 x 10-8 (iv) 1.0001 x 109

(v) 5.8 x 1012 (vi) 3.61492 x 106

Q3 :

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 of a thick paper is 0.07 mm