Boron Has Two Stable Isotopes, 105b510b and 115b511b. Their Respective Masses Are 10.01294 U and 11.00931 U, and the Atomic Mass of Boron is 10.811 U. Find the Abundances of 105b510b and 115b511b. - Physics

Advertisements
Advertisements
Numerical

Boron has two stable isotopes, `""_5^10"B"` and `""_5^11"B"`. Their respective masses are 10.01294 u and 11.00931 u, and the atomic mass of boron is 10.811 u. Find the abundances of  `""_5^10"B"`  and `""_5^11"B"`.

Advertisements

Solution

Mass of boron isotope `""_5^10"B"`, m1 = 10.01294 u

Mass of boron isotope `""_5^11"B"`, m2 = 11.00931 u

Abundance of `""_5^10"B"`, η1 = x%

Abundance of `""_5^11"B"`, η2 = (100 − x)%

Atomic mass of boron, m = 10.811 u

The atomic mass of boron atom is given as:

`"m" = ("m"_1η_1 + "m"_2η_2)/(η_1 + η_2)`

`10.811 = (10.01294 xx "x" + 11.00931 xx (100 -"x"))/("x" + 100 - "x")`

1081.11 = 10.01294 x + 1100.931 − 11.00931 x

∴ x = `(19.821)/0.99637`

= 19.89%

And 100 − x = 80.11%

Hence, the abundance of `""_5^10"B"` is 19.89% and that of `""_5^11"B"` is 80.11%.

  Is there an error in this question or solution?
Chapter 13: Nuclei - Exercise [Page 462]

APPEARS IN

NCERT Physics Class 12
Chapter 13 Nuclei
Exercise | Q 13.1 (b) | Page 462
NCERT Physics Class 12
Chapter 13 Nuclei
Exercise | Q 1.2 | Page 462

RELATED QUESTIONS

In the study of Geiger-Marsdon experiment on scattering of α particles by a thin foil of gold, draw the trajectory of α-particles in the coulomb field of target nucleus. Explain briefly how one gets the information on the size of the nucleus from this study.

From the relation R = R0 A1/3, where R0 is constant and A is the mass number of the nucleus, show that nuclear matter density is independent of A


Two stable isotopes of lithium `""_3^6"Li"` and `""_3^7"Li"` have respective abundances of 7.5% and 92.5%. These isotopes have masses 6.01512 u and 7.01600 u, respectively. Find the atomic mass of lithium.


What do you mean by polar molecules and non-polar molecules? Give ‘one’ example each.


Name a material which is used in making control rods in a nuclear reactor.


Write one balanced equation to show Emission of `beta^-` (i.e. a negative beta particle)


With the help of a suitable example and an equation, explain the term pair production.


Two nuclei have mass numbers in the ratio 1: 2. What is the ratio of their nuclear densities?


If neutrons exert only attractive force, why don't we have a nucleus containing neutrons alone?


The mass number of a nucleus is


Potassium-40 can decay in three modes. It can decay by β-emission, B*-emission of electron capture. (a) Write the equations showing the end products. (b) Find the Q-values in each of the three cases. Atomic masses of `""_18^40Ar` , `""_19^40K` and `""_20^40Ca` are 39.9624 u, 39.9640 u and 39.9626 u respectively.

(Use Mass of proton mp = 1.007276 u, Mass of `""_1^1"H"` atom = 1.007825 u, Mass of neutron mn = 1.008665 u, Mass of electron = 0.0005486 u ≈ 511 keV/c2,1 u = 931 MeV/c2.)


The atomic mass of Uranium `""_92^238"U"` is 238.0508 u, while that of Thorium `""_90^234"Th"` is 234.0436u, and that of Helium `""_2^4"He"` "is 4.0026u. Alpha decay converts `""_92^238"U"` into `""_92^234"Th"` as, shown below:

`""_92^238"U" -> ( ""_90^234"Th" + ""_2^4"He" + "Energy" )`


What is a neutrino?


Find the Q-value and the kinetic energy of the emitted α-particle in the α-decay of `""_86^220"Rn"`.

Given `"m"(""_88^226"Ra")` = 226.02540 u, `"m"(""_86^222 "Rn")` = 222.01750 u, 

`"m"(""_86^220 "Rn")`= 220.01137 u, `"m"(""_84^216 "Po")`= 216.00189 u.


Atomic mass unit (u) is defined as ________ of the mass of the carbon (12C) atom.


Nuclides with same neutron number N but different atomic number Z are called ______.


A nucleus of mass number A has a radius R such that ______.


A vessel contains oil (density 0.8 g/cm3) over mercury (density 13.6 g/cm3). A sphere of homogeneous composition floats with half its volume immersed in mercury and the other half in oil. The density of the material of the sphere in g/cm3 is ______.


A nucleus yYx emits one α and two β particles. The resulting nucleus is ______.


Two cars of mass m1 and m2 are moving in circles of radii r1 and r2, respectively. Their speeds are such that they make complete circles at the same time t. The ratio of their centripetal acceleration is:


The valance electrons in alkali metal is a:-


The mass number of a nucleus is equal to the number of:-


Are the nucleons fundamental particles, or do they consist of still smaller parts? One way to find out is to probe a nucleon just as Rutherford probed an atom. What should be the kinetic energy of an electron for it to be able to probe a nucleon? Assume the diameter of a nucleon to be approximately 10–15 m.


Deuteron is a bound state of a neutron and a proton with a binding energy B = 2.2 MeV. A γ-ray of energy E is aimed at a deuteron nucleus to try to break it into a (neutron + proton) such that the n and p move in the direction of the incident γ-ray. If E = B, show that this cannot happen. Hence calculate how much bigger than B must E be for such a process to happen.


James Chadwick, in 1932 studied the emission of neutral radiations when Beryllium nuclei were bombarded with alpha particles. He concluded that emitted radiations were neutrons and not photons. Explain.


Mass numbers of two nuclei are in the ratio of 4 : 3. Their nuclear densities will be in the ratio of ______.


Which of the following are the constituents of the nucleus?


What conclusion is drawn from Rutherford’s scattering experiment of α-particles?


Share
Notifications



      Forgot password?
Use app×