Lithium has a work function of 2.3ev. If 400nm light is incident on it, what is the maximum kinetic energy ? Chemistry Bohr Model of the Atom Calculations with wavelength and frequency
No. A comma precedes such as when what follows is an example of whatever went before. In this case, it is nonrestrictive. (For nonrestrictive constructions: use a comma.).
This is why some of us were taught to use comma before 'but', and some of us were not. Generally speaking, in the UK, writers tend not put a comma before the conjunction. In the US, however, writers tend to use a comma.