AP EAMCET202017 Sep 2020Morning ShiftPhysicsDual Nature of MatterActual
If ultraviolet radiation of (6.2 eV ) falls of an aluminium surface, then kinetic energy of the fastest emitted electron is (work-function (=4.2 eV ) )
Options
- A(3.2 10⁻¹⁹ ~J )
- B(32 10⁻²¹ ~J )
- C(7 10⁻²⁵ ~J )
- D(9 10⁻³¹ ~J )
Correct answer
A. (3.2 10⁻¹⁹ ~J )
Step-by-step solution
Energy of ultraviolet radiation, (E=6.2 eV ) Work-function, ( =4.2 eV ) ( ) According to Einstein's photoelectric equation, kinetic energy of the fastest emitted electron, ( aligned 1 2 m v_ ^2 & =E- =6.2-4.2=2 eV & =2 1.6 10⁻¹⁹ ~J 1 2 m v_ ^2 & =3.2 10⁻¹⁹ ~J aligned )