Hi Sainath,
Did you add a g to all of the values into each cell of the column (or
row) of X values?
If that's the case then the x values are no longer recognised and Excel
converts them to number labels 1,2,3 etc. Did you notice the change in
the X axis value labels?
With such a change in the X values the R squared value changes as does
the equation of the trendline.
Does this describe what you have observed? If yes then you should only
type the units Value (X) axis: and Value (Y) axis: boxes under the
Titles tab of the Chart options dialog.

Ken Johnson