Question
Question: Radius of nucleus varies as \(R = {R_0}{\left( A \right)^{\dfrac{1}{3}}}\) , where \({R_0} = 1.3\) F...
Radius of nucleus varies as R=R0(A)31 , where R0=1.3 Fermi. What is the volume of Be8 nucleus (approx.) [ A=atomic mass]?
A. 7×10−38cc
B. 7×10−29cc
C. 7×10−45cc
D. None of these
Solution
We need to substitute the value of the atomic mass in the given expression to calculate the radius of the Be8 nucleus. We need to calculate the volume of the Be8 nucleus. The volume of an atom is given as 34πR3 Here R is the radius of the nucleus of the atom. The given unit of radius is in Fermi and the options are in cubic centimetre.
Complete step by step answer:
We are given with the expression to calculate the radius of the nucleus of an atom. We are given with a Be8 atom. The atomic mass of an atom is given as 8 .
The radius of the nucleus of the Be8 atom will be given as:
R=R0(8)31
⇒R=R0×2
We are given that R0=1.3 Fermi, therefore the radius of the Be8 atom’s nucleus will be:
R=1.3×2 Fermi
⇒R=2.6 Fermi
The relation between Fermi and centimetre is 1Fermi=10−13cm
⇒R=2.6×10−13cm
Therefore, the radius of the nucleus of Be8 atom is R=2.6×10−13cm
The volume of the nucleus will be given as:
V=34πR3
Here, V is the volume.
Substituting the value of radius of the nucleus of Be8 atom, we get
V=34π(2.6×10−13)3
⇒V=4.18×(2.6×10−13)3
⇒V=7.36×10−38cc
⇒V≈7×10−38cc
This is the approximate volume of the Be8 nucleus.
So, the correct answer is “Option A”.
Additional Information:
Chronic beryllium disease also known as CBD is responsible for causing scarring of the lung tissue. It occurs when a person inhales dust or fumes of beryllium which is a naturally occurring lightweight material.
Note:
The given unit of radius was in Fermi, converting it to centimeters.
The given expression for radius is for the radius of the nucleus and not the radius of the atom.
Radius of the nucleus is proportional to the cube root of its atomic mass.
All the mass of an atom is considered to be present in the nucleus.