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.).
Other than that, do it the way you want.  Hope this helps     According to the 6th Edition of the Publication Manual of the APA, space twice after punctuation marks at the end of a sentence. Section 4.01 - last sentence.