EAMCET Engineering 2004 Solved Paper

Electrons ejected from the surface of a metal, when light of certain frequency is incident on it, are stopped fully by a retarding potential of 3 volts. Photoelectric effect in this metallic surface begins at a frequency 6×1014 s−1. The frequency of the incident light in s−1 is : [Planck's constant =6.4×10−34 Js, charge on the electron =1.6×10−19C]