When photon of energy 4.0 eV strikes the surface of a metal A, the ejected photoelectrons have maximum kinetic energy  ${\mathrm{T}}_{\mathrm{A}} \mathrm{eV}$ and de-Broglie wavelength  ${\lambda }_A$. The maximum kinetic energy of photoelectrons liberated from another metal B by photon of energy 4.50 eV is  ${\mathrm{T}}_{\mathrm{B}}=\left({\mathrm{T}}_{\mathrm{A}}-1.5\right) \mathrm{eV}$. If the de-Broglie wavelength of these photoelectrons  ${\lambda }_B=2{\lambda }_A$, then the work function of metal B is: