Kinetic energy of a photoelectron

[Krushnaraj Pandya]

Homework Statement

Why is the value hf-w equal to maximum kinetic energy (not just kinetic energy) for a photoelectron?

2. The attempt at a solution
w is the energy needed for electron to escape the surface, so the rest should convert to KE, and no such need for defining KE(max) should be needed.
I'd be grateful if someone could resolve my process of thinking here

 

[TSny]

Not all electrons require the same amount of work to remove them from the metal. W is defined to be the minimum amount of work required. That is, W is the amount of energy required to remove those electrons that are easiest to dislodge from the metal.

 

[Krushnaraj Pandya]

Not all electrons require the same amount of work to remove them from the metal. W is defined to be the minimum amount of work required. That is, W is the amount of energy required to remove those electrons that are easiest to dislodge from the metal.

Got it! Thank you :D