Surface of certain metal is first illuminated with light of wavelength λ1=350 nm and then, by light of wavelength λ2=540 nm. It is found that the maximum speed of the photo electrons in the two cases differ by a factor of (2). The work function of the metal (in eV) is close to:
(Energy of photon)=λ (in nm)1240 eV
[Main 9 Jan. 2019 I]
(a) 1.8
(b) 2.5
(c) 5.6
(d) 1.4