In the photoelectric effect the electrons are emiited instantaneously from a given metal plate when it is irradiated with radiation of frequency equal to or greater than some minimum ferquency, is called the threshold frequency.According to Planck's idea, light may be considered to be made up discrete particles called photons.Each photon carries energy equal to hv.When this photon collides with the electron of the metal, the electron acquires energy of the emitted electron is given by :
`hv=K.E_("maximum")+PE=(1)/(2)m u^(2)+PE`
If the incident rediation is of threshold frequency the electron will be emitted without any kinetic energy
i.e `hv_(0)`
`:.(1)/(2)m u^(2)=hv-hv_(0)`
A plot of kinetic energy of the emitted electron versus frequency of the incident radiation yields a straight line given as :

A laser producting monochromatic lights of different wavelenght is uesd to eject electrons from the sheet of gold having threshold frequency `6.15xx10^(14)s^(-1)` Which of the following incident rediation will be suitable for the ejecting of electrons ?

Options

A. `1.5` moles of photons having frequency `3.05xx10^(14) s^(-1)`
B. `0.5` moles of photon of frequency `12.3xx10^(12) s^(-1)`
C. One photon with frequency `5.16xx10^(15) s^(-1)`
D. All of the above

Answer

C

Explanation

The interaction between photon and electron is always one to one for ejection of photoelectrons, Frequency of incident radiation `gt` threshold frequency `:. 5.16xx10^(15) gt 6.15xx10^(14)`