# 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

**Solution:**

Standard form of exponents is used to represent a very small or large number following a certain set of rules.

(i) 1 micron is equal to 1/1000000 m

1/1000000 = 0.000001 = 1 × 10^{−6}m

(ii) 0.00000000000000000016

0.00000000000000000016 =16/100000000000000000000

= 1.6 × 10 / 10^{20}

= 1.6 × 10^{−19} coulomb

(iii) 0.0000005 m

0.0000005 m = 5/10000000

= 5/10^{7}

= 5 × 10^{−7}m

(iv) 0.00001275 m

0.00001275 m = 1275/100000000

= 1.275 × 10^{3}/10^{8}

= 1.275 × 10^{−5}m

(v) 0.07 mm

0.07 mm = 7/100

= 7/10^{2}

= 7 × 10^{−2}mm

**☛ Check: **NCERT Solutions for Class 8 Maths Chapter 12

**Video Solution:**

## 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

Class 8 Maths NCERT Solutions Chapter 12 Exercise 12.2 Question 3

**Summary:**

The number appearing in the following statements are expressed in standard form as follows:(i) 1 micron is equal to 1/1000000 m = 1 × 10^{-6}m (ii) Charge of an electron is 0.000,000,000,000,000,000,16 coulomb = 1.6 × 10^{−19} coulomb (iii) Size of a bacteria is 0.0000005 m = 5 × 10^{−7}m (iv) Size of a plant cell is 0.00001275 m = 1.275 × 10^{−5}m (v) Thickness of a thick paper is 0.07 mm = 7 × 10^{−2}mm

**☛ Related Questions:**

- Express the following numbers in standard form. (i) 0.0000000000085 (ii) 0.00000000000942 (iii) 6020000000000000 (iv) 0.00000000837 (v) 31860000000
- Express the following numbers in 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
- 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.

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