# EX.13.3 Q4 Exponents-and-Powers Solutions- NCERT Maths class 7

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## Question

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

(a) The distance between Earth and Moon is $$384,000,000 \rm\, m$$

(b) Speed of light in vacuum is $$300,000,000 \rm \,m/s$$

(c) Diameter of the Earth is $$1,27,56,000\rm \,m$$

(d) Diameter of the Sun is $$1,400,000,000 \rm\,m$$

(e) In a galaxy there are on an average $$100,000,000,000$$ stars

(f) The universe is estimated to be about $$12,000,000,000$$ years old

(g) The distance of the Sun from the centre of the Milky Way Galaxy is estimated to be $$300,000,000,000,000,000,000 \rm\,m$$

(h) $$60,230,000,000,000,000,000,000$$ molecules are contained in a drop of water weighing $$1.8 \rm\,gm$$

(i) The earth has $$1,353,000,000$$ cubic $$\rm{km}$$ of sea water

(j) The population of India was about $$1,027,000,000$$ in March $$2001$$

## Text Solution

(a) The distance between Earth and Moon is $$384,000,000 \rm\, m$$.

Standard Form $$= 3.84\times10^{8} \rm\, m$$

(b) Speed of light in vacuum is $$300,000,000 \rm \,m/s$$.

Standard Form $$= 3\times10^{8} \rm \, m/s$$

(c) Diameter of the Earth is $$1,27,56,000\rm \,m$$.

Standard Form $$= 1.2756\times10^{7}\rm\, m$$

(d) Diameter of the Sun is $$1,400,000,000 \rm\,m$$.

Standard Form $$= 1.4\times10^{9} \rm\,m$$

(e) In a galaxy there are on an average $$100,000,000,000$$ stars.

Standard Form $$= 1\times10^{11}$$ stars

(f) The universe is estimated to be about $$12,000,000,000$$ years old.

Standard Form $$= 1.2\times10^{10}$$years old

(g) The distance of the Sun from the centre of the Milky Way Galaxy is estimated to be $$300,000,000,000,000,000,000 \rm\,m$$.

Standard Form $$= 3\times10^{20}\rm\, m$$

(h)  $$60,230,000,000,000,000,000,000$$ molecules are contained in a drop of water weighing $$1.8 \rm\,gm$$.

Standard Form $$= 6.023\times10^{22}$$ molecules

(i) The earth has $$1,353,000,000$$ cubic $$\rm{km}$$ of sea water.

Standard Form $$= 1.353\times10^{9} \rm cubic \,\rm\, km$$

(j) The population of India was about $$1,027,000,000$$ in March $$2001$$.

Standard Form $$= 1.027\times10^{9}$$

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