Atoms and Nuclei Questions & Answer PDF for NEET

Atoms and Nuclei Questions & Answer PDF for NEET

These physics questions are prepared by our live learns teams there are so many multiple choice questions on Atoms and nuclei Here we give below the important questions of class 12 physics Unit -viii Atoms and nuclei is the most important chapter in physics so these Atoms and nuclei questions are very important for Competitive Exams. and we are provide it full of free to ace your exams do check it.



1. Atomic Nucleus ?

it is represented by ZXA

where Z is charge number = number of protons.

A is the number of neutrons= (A-Z).

2. What is the Atomic Mass Unit ? 

A atomic mass unit is defined as the th of the actual mass of an 12

atom of carbon 12.


(i) What are  Isotopes?

Isotopes are the atoms of the same element which have the same atomic number but different mass numbers, e.g. H, H and H° are isotopes of hydrogen.

(ii) What are the Isobars? 

Isobars are the atoms of different elements which have the same value of mass number but different atomic numbers e.g 20Ca* and Ar are isobars with E A = 40.

(iii) What are the Isotones ?

Isotones are the atoms of different elements having the same number of neutrons.

e.g. ,C,K andCa are isotones With number of neutrons 20.


(i) What is the Mass Defect?

It is defined as the difference between the mass of the nucleus and the sum of the masses of its constituent nucleons.

(ii) What is Binding Energy ? 

Binding energy of a nucleus is defined as the energy required to split the given nucleus into its constituent nucleons.

(iii) What is the Binding Energy per Nucleons (EB) ?

OCME It is defined as the average energy required to extract one nucleon from the nucleus.

So E, EpJA. 

It is maximum for IRON i.e., 8.8 MeV nucleon.

5. What is the Binding Energy Curve?

It is a curve drawn between the mass number, A and the binding energy per nucleon, B. The curve shows that the binding energy of lightweight nuclei and heavy weight nuclei are smaller than that of middle weight nuclei. This shows that the middle weight nuclei are more stable than lightweight and heavyweight nuclei.

6. What is Radio-Isotopes?

 The radioactive isotopes of normal stable elements are called radio-isotopes. They find their use in the field of medicine, agriculture, industry and food preservation. There are 40 natural radioactive isotopes, 1500 artificial radioactive isotopes.

7. What is Nuclear Fission in atoms ?

 The splitting of a heavy nucleus into two or more lighter nuclei of comparable masses along with the release of a large amount of energy is called nuclear fission. e.g oU5 + sBal Kr7 + 3,n + 200 MeVV

8. What is Nuclear Fusion ?

It is the phenomenon of the combination of two or more lighter nuclei to form a comparatively heavy nucleus along with the emission of a huge amount of energy.

HO(z) e.g. 4,H He + 2,e+24.7 MeV

This is the source of the sun.


 (i) What is the Nuclear Chain Reaction?

The nuclear reaction which is self sustained and multiples under suitable conditions in a geometrical progression is known as nuclear chain reaction.

(ii) What is the Controlled Chain Reaction?

 It is a reaction in which the reproduction factor is equal to one.

(iii) What is the Reproduction Factor ? 

It is defined as not  the ratio of the number of fissions produced by a given generation of neutrons to the number of fissions of the proceeding generation of neutrons.

10.What is half lived briefly ? 

 Probability that a particular nucleus decays in ‘n’ half lives is (1-1/2ñ)

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