We know the de Broglie wavelength of a particle is given by,

where h is the Planck’s constant, m is the mass and v is the velocity

where p=mv.

Since h is a constant and the particles have the same de Broglie wavelengths, their momenta are the same.

The kinetic energy of a particle with de Broglie wavelength is given by,

Hence, their energies are different.

m₁ > m₂

Hence, K₂ > K₁