What is the minimum kinetic energy on an electron traveling in crown gl to create Cerenkov Radiation?

Cerenkov Radiation occurs when the electron travels over the speed of light in crown gl, which is c/n, or about 2x10^8 m/s. Now, use the definition of KE as mc^2/gamma - mc^2 using c=3x10^8 m/s and gamma's v as 2x10^8 m/s^2. This gives about 2.797x10^(-14) Joules, or about 174 578.067 electron volts.