Question

1 pm is equals to :
A.${{10}^{-10}}m$
B.${{10}^{-11}}m$
C.${{10}^{-12}}m$
D.${{10}^{-15}}m$

Answer 1

Hint: Picometer which is one of the units of length is used to measure the distance which is smaller than a metre. When we multiply the length with ${{10}^{-3}}m$ at each step then we obtain the shorter units of length. Picometre is equal to one trillionth $\left( \dfrac{1}{1000000000000} \right)$ of a meter.

Complete answer:
From your chemistry lesson you have learned about the units of length and its S.I unit.
The unit of length is an internationally accepted standard unit which is used for the measurement of length. S.I system of units is the most commonly used system for the measurement. In S.I unit the unit of length is given as metre which is expressed as m. S.I unit system is an M.K.S system. The full form of M.K.S is the Metre Kilogram Second system.
According to the C.G.S (Centimetre Gram Second) system the unit of length is centimetre (cm). The unit of length, metre and centimetre are related to each other as follows:
\[1m=100cm\]
\[or,1cm={{10}^{-2}}m\].
Now, if we want to measure the shorter lengths than cm, then there are other units which we are going to see. As we know that meter is the S.I unit therefore all the units of lengths are related with metre. They are given as:
Milimetre: $1mm={{10}^{-3}}m$
Micrometre: $1\mu m={{10}^{-6}}m$
Nanometre: $1nm={{10}^{-9}}m$
Picometre: $1pm={{10}^{-12}}m$
Femtometre: $1fm={{10}^{-15}}m$
Hence, picometre is the unit of length in the metric system which is equal to ${{10}^{-12}}m$.

Thus the correct option will be (C).

Note:
Picometer is used for the measurement of lengths which is of small order. Picometer has a wide range of applications in quantum chemistry, particle physics , quantum physics, acoustic, etc. The unit of lengths can go beyond femtometre also but the present scientific technology is not observed or measured length smaller than femtometre.