Kinetic energy of electron revolving in an orbit of hydrogen is +0.54 eV.  Angular momentum of electron revolving in the same orbit of hydrogen atom is h2π=h-

In hydrogen atom, + K.E of electron =.-T.E of electron ;Thus T.E=-0.54 eV;            T.E=Z2n2×E1E1=-13.6 eV ;  -0.54 eV=12n2×E1E1=-13.6 eV;                  n=5; Angular momentum=nh2π=5h2π