# What is the stoping voltage

Hi everyone.

I came across with a problem in my question book which was

"what is the stoping voltage when a UV ligh with WaveLength 200nm hits a clean gold surface.(5.1v Work Function.)"

I have found the frequency which is $$1.5^15 Hz$$ I know the $$W$$ Therefore I can let $$Ekmax=(hf)-W$$ and $$Ekmax=qV$$

But when I put the equations together they dont make any sence to me.
$$V=\frac{(hf)-W}{q}$$

Can someone help me through this plz

dextercioby