CBSE Class 12-science Answered

(a) There is minimum frequency of incident radiation below which no electrons are emitted.

Above statement is true .

Einstein equation of photo electric phenomenan is

where h is planck's constant , ν is frequency of incident electromagnetic equation , w is workfuntion of photoelectric material ,

m is mass of electron and v is speed of electron .

As per above equation, energy of incident photon  is sum of workfunction and kinetic energy of electron.

In otherwords some threshold energy is required in the form work function and remaining energy of incident radiation appears 

in the form of kinetic energy of electron. If energy of the photon in  incident radiation  is less than this threshold value , energy is insufficient

to knock out the electron from photoelectric material.

Hence no electron is emitted if the energy of incident radiation is less than the workfunction value.

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(d) Maximum kinetic energy depends only on frequency of incident radiation.

In the above Einstein equation of photoelectric phenomena , workfunction is constant that is characterstic of material.

Hence kinetic energy is function of energy of photon of incident radiation . 

Energy of photon depends on frequency of incident radiation .

Hence , maximum kinetic energy depends only on frequency of incident radiation