# 3.Express the number appearing in the following statements in standard form. (i) 1 micron is equal to $$\frac { 1 }{ 1000000 }$$ 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.

(i)We have 1 micron=$$\frac { 1 }{ 1000000 }$$

$$=\frac{1}{10^6}m=10^{-6}$$

(ii)We know charge of an electron=0.000,000,000,000,000,000,16

$$\frac{16}{1,000,000,000,000,000,000,00}=\frac{1.6\times 10}{1,000,000,000,000,000,000,00}$$

$$=\frac{1.6\times 10}{10^{20}}=1.6\times 10^{1-20}=1.6\times 10^{-19}$$

(iii)We have size of bacteria=0.0000005m

$$=\frac{5}{10000000}m=\frac{0.5\times 10}{10^7}m$$

$$=0.5\times 10^{1-7}m=0.5\times 10^{-6}m$$

$$=5\times 10^{-7}m$$

(iv)We have size of plant cell=0.00001275m

$$=\frac{1275}{100000000}m=\frac{1.275\times 10^3}{10^8}m$$

$$=1.275\times 10^{3-8}m=1.275\times 10^{-5}m$$

$$=1.275\times 10^{-5}m$$

(v)We have thickness of paper=0.07mm

$$=\frac{7}{100}mm=\frac{0.7\times 10}{10^2}mm$$

$$=0.7\times 10^{1-2}mm=0.7\times 10^{-1}mm$$

$$=7\times 10^{-2}mm$$