Class 8 Powers and Exponents

Chapter 12: Powers and Exponents

Ex 12.1 

1. Evaluate

i) 3^-2 

ii) (-4)^-2 

iii) (1/2) ⁻⁵

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

i) (-4)⁵ ÷ (-4)⁸

ii) (1/2³)²

iii) (-3)⁴ × (5/3)⁴

iv) (3^-7 ÷ 3^-10) × 3^-5

v) 2^-3 × (-7)^-3

3. Find the value of

i) (3⁰ + 4^-1) × 2²

ii) (2^-1 × 4^-1) ÷ 2^-2

iii) (1/2)^-2 + (1/3)^-2 + (1/4)^-2

iv) (3^-1 + 4^-1 + 5^-1)⁰

v) {(-2/3)^-2}²

4. Evaluate

i) 8^-1 × 5³/2^-4

ii) (5^-1 × 2^-1) × 6^-1

5. Find the value of m for which 5^m ÷ 5^-3 = 5⁵

6. Evaluate 

i){(1/3)^-1 – (1/4)^-1}^-1

ii) (5/8)^-7 × (8/5)^-4

^{7. Evaluate}

i) (25 × t^-4) / (5^-3 ×10 × t^-8)

ii) (3^-5 × 10^-5 × 125) / 5^-7 × 6^-5

Ex 12.2 

1. Express the following numbers in standard form. 

(i) 0.0000000000085 

(ii) 0.00000000000942 

(iii) 6020000000000000 

(iv) 0.00000000837 

(v) 31860000000 

2. Express the following numbers in the usual form

(i) 3.02 × 10⁻⁶ 

(ii) 4.5 × 10⁴

(iii) 3 × 10⁻⁸

(iv) 1.0001 × 10⁹ 

(v) 5.8 × 10¹² 

(vi) 3.61492 × 10⁶

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

(i)  1 micron is equal to 1/ 1000000 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 

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?

Ex 12.1 and Ex 12.2 Free PDF Download 

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