) two wires a and b of the same material and equal length but of radii r and 2r are soldered coaxially. the free end of b is twisted by an angle . find the twis

) Two wires A and B of the same material and equal length but of radii r and 2r are soldered coaxially. The free end of B is twisted by an angle . Find the twist angle 6 at the junction and the torsional rigidity of the complete wire.