kinetic energy of electron moving in orbit of hydrogen atom having de Broglie's wavelength 10A is
We know from bohr model of atom:
mvr = n h/2 pi
We also know that kinetic energy of any particle is given by 1/2 mv^2
we also know by de broglie hypothesis de broglie wavelength = lamda= h/mv
Now you can manipulate these three equations and get the kinetic energy of electron.