What is packing fraction ? How it is related to stability of nuclei ?

What is wave number ? How it is related to wavelength ?

What is gravitational field. How it is related to gravitational potential?

What is emissivity of a body ? How it is related to absorbing power ?

How resonance energy is related to stability?

How DeltaT_f is related with molality ?

What do you mean by electric flux ? What is its unit ? How it is related to flux density ?