The kinetic energy of the electron in the first orbit of hydrogen is given by:
\[
K.E. = \frac{1}{2} mv^2
\]
From Bohr's model, the total energy of the electron in the first orbit is \( -13.6 \, \text{eV} \). The kinetic energy is half of the total energy, and its positive value is:
\[
K.E. = 3.4 \, \text{eV}
\]
Thus, the kinetic energy of the electron in the first orbit is \( 3.4 \, \text{eV} \).