How to Draw a given Character in exact height ?

I am drawing the text using Graphics.DrawString() method, But the text height drawn is not same as which i gave.

For Eg.

Font F=new Font("Arial", 1f,GraphicUnit.Inch);

g.DrawString("M", F,Brushes.red,new Point(0,0));

By using the above code, i'm drawing the text with height 1 inch, but the text drawn is not exactly in 1 inch. 
I need to Draw the text in Exact height which i'm giving. Thanks in advance..