The work functions of Ag , Mg , K and Na respectively in eV are 4.3,3.7,2.25,2.30 . When an electromagnetic radiation of wavelength of 300 ~nm is allowed to fall on these metal surface, the number of metals from which the electrons are ejected is ( e V =1.6022 10⁻¹⁹ ~J )

Step-by-step solution

Energy of EM wave used aligned & E= h c = 6.6 10⁻³⁴ 3 10^8 300 10⁻⁹ & E=0.066 10⁻¹⁷=6.6 10⁻¹⁹ ~J aligned Metals surface which have work function less than or equal to 6.6 10⁻¹⁹ ~J will eject electrons on radiation with light of 300 ~nm . Work function of Ag =4.3 eV 1.6022 10⁻¹⁹=6.89 10⁻¹⁹ ~J aligned & Mg =3.7 eV 1.6022 10⁻¹⁹=5.93 10⁻¹⁹ ~J & ~K =2.25 eV 1.6022 10⁻¹⁹=3.60 10⁻¹⁹ ~J & Na =2.30 eV 1.6022 10⁻¹⁹=3.68 10⁻¹⁹ ~J aligned Only Mg , K and Na have their work function less than 6.6 10⁻¹⁹ ~J hence, they will eject