Anand Deo

First of all we have to find the enenry(E) of Photon by using the Formula

E=hc/λ

here 'h' is the Plank's constant. 

'c' is the Speed of light

and λ is the wavelength

Now we have to think what is the term "WORK FUNCTION" used in the Question

WORK FUNCTION is the MINIMUM amount of energy required to release a ELECTRON from the Metal

It is given in the Question

Now we are able to give the answer of the 2nd part of the Question

i.e Kinetic energy of emission== Total energy of photon- Energy required for emission(work function)

Now the question is WHAT IS THE VELOCITY OF PHOTOELECTRON??

From 2nd part of Question We know the Kinetic Energy of Photoelectron.

Use the formula,

K.E= ½*mass*(velocity)²

for the value of "mass of electron" , "plank's constant" and "velocity of light "use your book.

THANK YOU