# Nuclear Physics Formulas

Nuclear physics is part of physics that tells about the interactions in the atomic nuclei. There are lots of concepts since its a vast subject like radioactivity, decay rate, half life period, nuclear reactions like fusion and fission. So only important formulas are discussed here.

If initially N

N = No of Atoms that remains after time t,

N

Decay rate depends on rate of change in number of atoms to the time t.

It is given by,

N = No of Atoms that remains after time t,

$\lambda$ is decay constant.

Decay constant formula is,

A is activity and N is the no of atoms remaining.

Half-life period t

Mean life time of an atom before decay is given by,

Mass number A formula is given by,

N is neutrons.

Nuclear radius R formula is given by,

_{o}number of atoms are present then,Number of atoms = N

Where, _{o}= N + N_{D.}_{}N = No of Atoms that remains after time t,

N

_{D}= No of atoms that gets decayed at time t.Decay rate depends on rate of change in number of atoms to the time t.

It is given by,

Activity A = $\frac{dN}{dt}$.

or

Activity A = $\lambda$ N.

Where, N = No of Atoms that remains after time t,

$\lambda$ is decay constant.

Decay constant formula is,

Decay constant $\lambda$ = $\frac{A}{N}$.

Where, A is activity and N is the no of atoms remaining.

Half-life period t

_{1/2 }of the radio isotope is given by,t

Where, $\lambda$ is decay constant._{1/2}= $\frac{0.693}{\lambda}$.Mean life time of an atom before decay is given by,

$\tau$ = $\frac{1}{\lambda}$.

Where, $\lambda$ is decay constant.Mass number A formula is given by,

A = Z + N.

Where, Z is number of protons,N is neutrons.

Nuclear radius R formula is given by,

R = R

A is nucleon number._{o}A^{1/3}.^{Where, Ro is radius of nucleon (1.3 fm),}