Threshold frequency, v_(0) is the minimum frequency which a photon must possess to eject an electron from a metal. It is different for different metals. When a photon of frequency 1.0 xx 10^(15) s^(-1) was allowed to hit a metal surface, an electron having 1.988 xx 10^(-19)J of kinetic energy was emitted. Calculate the threshold frequency of this metal. Show that an electron will not be emitted if a photon with a wavelength equal to 600 nm hits the metal surface.

Threshold frequency, v_(0) is the minimum frequency which a photon mus

1.	Threshold frequency, v_(0) is the minimum frequency which a photon must possess to eject an electron from a metal. It is different for different metals. When a photon of frequency 1.0 xx 10^(15) s^(-1) was allowed to hit a metal surface, an electron having 1.988 xx 10^(-19)J of kinetic energy was emitted. Calculate the threshold frequency of this metal. Show that an electron will not be emitted if a photon with a wavelength equal to 600 nm hits the metal surface.
Answer» Solution :We KNOW thathv =`hv_(0)+ke` or `hv-ke =hv_(0)=-1.988xx10^(-19)` `hv_(0)=6.626 xx10^(-19)-1.988xx10^(-19)j` `hv_(0)=4.638xx10^(-19)j` `v_(0)=(4.638 xx10j)/(6.626xx10^(-34)=0.699xx10^(15)s^(-1)` when `lambda=600 nm =600 xx10^(-19) m` thus `v lt v_(0)`hence no electro will beemitted