Where this formula come from ?

Breaking chemical bonds does not turn their potential energy into kinetic energy. All bond dissociation enthalpies are positive (for stable bonds that actually exist), which means that breaking them is an endothermic or heat absorbing process, and therefore they absorb kinetic energy (heat is a transfer of molecular kinetic energy). What you might be thinking of is exothermic reactions, where the enthalpy of the reactants is lower than the products, and so the reaction releases heat, or increases the kinetic energy of the surroundings. The short answer to your question is "because energy is conserved, it has to go somewhere, and heat and light are the only places it can go."

I want to ask , where did this formula come from ?

this comes from photoelectric effect

I clearly understood photoelectric effect concept, how kinetic energy ( K.E) = absorbed energy - bond energy , Sir ?

according to photoelectric effect KE = hv - hv0 right. KE energy can also be correlated such a way with bond energy.. KE = absorbed energy - work function and work function is the minimum amount of energy that is required to relase electron right?? so why we can't corrected work function to energy required to break bonk ?? while both needs energy

ok sir , now I am able to understand it. thank you sir.