As shown in the figure bottom face of the sample is held rigidly bound and a shearing/tangential force #F# is applied on upper face of area #A#. The modulus of rigidity #G# is defined as the ratio of shear stress to the shear strain.

Shear stress#=F/A# and

shear strain #=tan theta=(Deltax)/l#

#Delta x# is the transverse displacement of the area on which force is acting and #l# is the initial length of the side.

#G -= "Shear stress"/"Shear strain"= (F / A)/ ((Δ x) / l)#

#=>G= (F l)/( A Δ x)" Pa"#

Inserting given values in SI units we get

#G= 10 xx(10/100)/( 0.05/100)#

#=>G= 10 xx(10)/( 0.05)#

#=>G=2.0xx10^3" Pa"#