The ratio of de-Broglie wavelengths of molecules of hydrogen and helium which are at temperature 27oC and 127oC respectively is xy . Find  x+y

de-Broglie wavelength λ=hmvrms , rms velocity of a gas particle at the given temperature (T) is given as 12mvrms2=32kT⇒vrms=3 kTm⇒mvrms=3 mk T∴λ=hmvrms=h3 mkT⇒λHλHe=mHeTHemHTH=4 (273+127)2 (273+27)=83