Question

If 1 Femto is ${{10}^{-x}}$, then $x=?$

Answer 1

Hint: Femto is a unit in a metric system that comes from a Danish work meaning fifteen.

Complete step by step answer:
The femto-meter is a Prefix of length in the metric system and it is equal to ${{10}^{-15}}$meters. Another name for Femto is Fermi and it was named in the honour of a famous experimental physicist Enrico Fermi, who had a great contribution in the field of Nuclear Physics and won a Nobel prize in Physics for his work on radioactivity. Fermi is an important length scale in nuclear physics as the Radius of a nucleus is of the order of fermi.
Now, we know that
1 Femto = $10^{-15}$
$\Rightarrow x=15$
The correct answer is $\Rightarrow x=15$.

Additional Information:
The fermi is a useful length scale in nuclear physics as we have to study the elements at atomic scale. The interatomic spacing between two nucleons ranges in the order of fermi. Protons and neutrons collectively known as nucleons are packed together in a space of a few fermis.
Some other commonly used prefixes in the metric system of units are:
Giga (G) $\text{=1}{{\text{0}}^{9}}$
Mega (M) $\text{=1}{{\text{0}}^{6}}$
Kilo (k) $\text{=1}{{\text{0}}^{3}}$
Hecto(h) $\text{=1}{{\text{0}}^{2}}$
Deka(da) $\text{=1}{{\text{0}}^{1}}$
Deci(d) $\text{=1}{{\text{0}}^{-1}}$
Centi(c) $\text{=1}{{\text{0}}^{-2}}$
Milli(m) $\text{=1}{{\text{0}}^{-3}}$
Micro$(\mu )$ $\text{=1}{{\text{0}}^{-6}}$
Nano(n) $\text{=1}{{\text{0}}^{-9}}$
Pico(p) $\text{=1}{{\text{0}}^{-12}}$

Note: Students should not get confused between Femto and Fermi, they both are equivalent to $\text{1}{{\text{0}}^{\text{-15}}}\text{meters}$.