Explain error of chromatic aberration.

The dispersive powers of two materials are 0.30 & 0.28 . They are used to construct two lenses which are kept in contact to eliminate chromatic aberration (that means the f_(v)=f_(r) the focal ) If the material of disperive power 0.30 is 10cm, then the focal lenght (for av, color) of the lens of other material is :

Explain error of a sum or a difference.

Explain Absolute Error, Relative Error and Percentage Error.

Explain : Rutherford atomic model can not explain stability of an atom