Courses

# Test: Atomic Nucleus

## 10 Questions MCQ Test Physics Class 12 | Test: Atomic Nucleus

Description
This mock test of Test: Atomic Nucleus for JEE helps you for every JEE entrance exam. This contains 10 Multiple Choice Questions for JEE Test: Atomic Nucleus (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Atomic Nucleus quiz give you a good mix of easy questions and tough questions. JEE students definitely take this Test: Atomic Nucleus exercise for a better result in the exam. You can find other Test: Atomic Nucleus extra questions, long questions & short questions for JEE on EduRev as well by searching above.
QUESTION: 1

### The nuclide 92U238 has all the following except​

Solution:

The nuclide (nucleus) consists of neutrons and protons (when combined called nucleons).
Thus,
No. of protons in 92U238 = 92,
No. of neutrons = 146 (238 – 92)
No. of nucleons = 238 (146 + 92)

QUESTION: 2

### Which one of the following statements about the atomic nucleus is accurate?

Solution:

Most nuclei are approximately spherical. The average radius of a nucleus with A nucleons is R = R0A1/3, where R0 = 1.2*10-15 m. The volume of the nucleus is directly proportional to the total number of nucleons. This suggests that all nuclei have nearly the same density.

QUESTION: 3

### Nucleus ”a” contains 5 protons and 5 neutrons and has radius R. The radius of nucleus ”b”, which contains 35 protons and 45 neutrons, is closest to:​

Solution:

R∝A1/3
A(mass no.)=n+p
R/x=(10/80)1/3
R/x=(13/23)1/3
R/x=1/2
X=2R

QUESTION: 4

Binding energy per nucleon is the ratio of

Solution:

Binding energy per nucleon is the ratio of the binding energy of a nucleus to the number of the nucleons.

Binding energy per nucleon = (Total binding energy) / (Number of nucleon)

Measure of stability of the nucleus: Larger the binding energy per nucleon, the greater the work that must be done to remove the nucleon from the nucleus, the more stable the nucleus.

QUESTION: 5

The atomic number Z of the nucleus is

Solution:

The atomic number or proton number (symbol Z) of a chemical element is the number of protons found in the nucleus of every atom of that element. The atomic number uniquely identifies a chemical element. It is identical to the charge number of the nucleus

QUESTION: 6

The density of nuclear matter is:

Solution:

We use the concept of conservation of energy and distance of closest approach in Rutherford's alpha scattering experiment to find the radius of the nucleus is proportional to the Mass Number. The consequence of this is that the density of the nucleus is a constant, independent of mass number for all nuclei.

QUESTION: 7

The radius of a nucleus is directly proportional to (A=mass number)​

Solution:

For A nucleons
R=Ro​A1/3 [Ro=constant]
So, R∝A1/3

QUESTION: 8

The volume of atom in comparison of volume of nucleus is of the order of​

Solution:

The ratio of the volume of the atom and the volume of the nucleus is 1015
The radius of an atomic nucleus is of the order of 10−13cm or 10−15m or one Fermi unit.
On the other hand, the radius of an atom is of the order of 10−8cm or 10−10m or one angstrom unit.
Note:
The radius of the nucleus is much smaller than atomic radius.
The ratio of atomic radius to radius of nucleus is 10−10m /10−15m ​=105
Volume is proportional to cube of radius.
The ratio of atomic radius to radius of nucleus is (105)3=1015

QUESTION: 9

The average binding energy of nucleus is

Solution:

Excluding the lighter nuclei, the average binding energy per nucleon is about 8 MeV. The maximum binding energy per nucleon occurs at around mass number A = 50, and corresponds to the most stable nuclei.

QUESTION: 10

The number of electrons in an atom X of atomic number Z and mass number A is​

Solution:

No of neutrons are given by: (A−Z)
Given an atomic number (Z) and mass number (A), you can find the number of protons, neutrons, and electrons in a neutral atom. For example, a lithium atom (Z=3,A=7 amu) contains three protons (found from Z), three electrons (as the number of protons is equal to the number of electrons in an atom), and four neutrons (7–3=4).