Question

Arrange the following lengths in order of their magnitude.
I. $1$ Angstrom
II. $1$ Micro
III. $1$ Fermi
IV. $1$ Light year

A. III, I, II,IV
B. I, II, III, IV
C. III, II, I, IV
D. II, III, I, IV

Answer 1

Hint: Angstrom is mainly used to measure wavelength. Micrometer, also known as a micron, is the metric unit of length measurement. Traditionally, the femtometer unit, also briefly called fermi, was used to measure the dimensions of atomic nuclei. A light-year is a distance unit. It is the distance in one year that light will travel.

Complete step by step answer:
- Angstrom ( ${A^ \circ }$ ) is a unit of length usually used to measure light wavelengths equal to ${10^{ - 10}}$ metres or $0.1$ nanometer. It is named after Anders Jonas Ångström, a ${19^{th}}$ -century Swedish physicist.
- The ångström is commonly used as a unit for d-spacings (the distance between atomic planes in a crystal), cell parameters, inter-atomic distances and x-ray wavelengths in crystallography, solid-state physics and chemistry, as these values are mostly in the $1 - 10\,{A^ \circ }$ range.
- A micron is a tiny measurement unit which measures length. That's another name for a "micrometre," which is a thousandth of a millimetre or a millionth of a metre. One micron is half the length of two microns, for instance.
- The micrometre, also known as the micron, is a metric unit of measurement with a length equal to $0.001\,mm$, or around $0.000039$ inches. $\mu m$ is the symbol. To measure the thickness or diameter of microscopic objects, such as microorganisms and colloidal particles, the micrometre is frequently used.
- In the International System of Units, the femtometer (fm) is a unit of duration, specified using the SI prefix system as ${10^{ - 15}}$ meter. Traditionally, the unit, also briefly called fermi, was used to calculate the dimensions of atomic nuclei. The word femtometer, not fermi, in the SI is the right name.
- We use light-years for most spatial objects to identify their size. About one Earth year a light-year is the time light travels. One light-year is nearly $9$ trillion kilometres ( $6$ trillion miles). That's a $6$ and behind it $12$ zeros.
Hence, we can see that III $ < $ I $ < $ II $ < $ IV

So, the correct answer is “Option A”.

Note:
Although all the units have different values they still measure either distances or size. Different units are used for measurement depending on the size of the particle or the distance travelled. Instead of trying to tell stuff about how much a particular animal weighs, a standard measuring method helps us to make straightforward comparisons.