Manipal Entrance Test 2015 Physics Paper

According to Einstein’s photoelectric equation,
E = hv - w
If Vs is retarding or stopping potential and v0 is the threshold frequency, then the above equation becomes
eVs=hv−hv0
hv=eVs+hv0
v=

eVs

h

+v0
Hence, e=1.6×10−19C
Vs=3V,v0=6×10−14‌Hz
Therefore, required frequency,
v=

1.6×10−19×3

6.63×10−34

+6×1014
=1.323×1015‌Hz