The ratio of the normal stress to the maximum shear stress on the plane of maximum shear stress is

Question

Plane stress at a point in a body is defined by principal stresses 3$\sigma$ and $\sigma$ . The ratio of the normal stress to the maximum shear stress on the plane of maximum shear stress is                 

         (a) 1             (b) 2               (c) 3            (d) 4