Question

The most suitable unit for expressing nuclear radius is:
a.) Micro
b.) Fermi
c.) Nanometer
d.) Angstrom

Answer 1

Hint: In order to solve the given problem first we will see the different units of distance used for calculating the small distances and small particles. Further we will see in detail the relation of each of the units given with the meter scale. Further we will see the basic size of the nucleus in terms of meters and further we will select the best unit for the calculation of the nuclear radius out of the given four options of the unit.

Complete step by step answer:
The most famous units of distance are millimetres, centimetres, metres, and kilometres in the metric system of measurement. In line with the Foreign System of Units, the SI distance unit is a metre.
There are a lot of units for the measurement of small distances such as micrometer, fermi, nanometer, angstrom etc.
Electron microscopes are used for measuring distances as short as the size of an atom. This includes beams of electrons controlled by electrical and magnetic fields. A resolution of Angstroms is required for electron microscopes.
The relation of each of the given unit with meter is as follows:
1 meter $ = {10^6}$ micrometer
1 meter $ = {10^{15}}$ fermi
1 meter $ = {10^9}$ nanometer
1 meter $ = {10^{10}}$ angstrom

Now let us see the nuclear radius in terms of meter.
According to the practical study the size of the atom is of the order $1 \times {10^{ - 10}}m$ . This means that the atomic radius is of the order of angstrom.
And the size of the nucleus is of the order $1.2 \times {10^{ - 15}}m$ . This means that the nuclear radius is of the order of fermi.
Hence, the most suitable unit for expressing nuclear radius is Fermi.
So, the correct answer is “Option B”.

Note: In order to solve such types of problems students must remember the relation between the different units of distance and the basic or the SI unit of distance which is meter. The SI unit “meter” acts as the bridge between different units of distance. Students must also remember the overall order of some special and common objects like atoms and nucleus.