AP EAMCET2009PhysicsDual Nature of Matter
A photon of energy E ejects a photoelectron from a metal surface whose work function is W₀ . If this electron enters into a uniform magnetic field of induction B in a direction perpendicular to the field and describes a circular path of radius r , then the radius r is given by, (in the usual notation)
Options
- A2 m (E-W₀ ) e B
- B2 m (E-W₀ ) e B
- C2 e (E-W₀ ) m B
- D2 m (E-W₀ ) e B
Correct answer
B. 2 m (E-W₀ ) e B
Step-by-step solution
From Einstein's equation gathered E=W₀+ 1 2 m v^2 2 (E-W₀ ) m =v gathered or A charged particle placed in uniform magnetic field experience a force F= m v^2 r aligned or & e v B & = m v^2 r or & r & = m v e B aligned array ll or & r= m 2 (E-W₀ ) m e B & r= 2 m (E-W₀ ) e B array