KVPY2016PhysicsDual Nature of Matter
Photons of wavelength are incident on a metal. The most energetic electrons ejected from the metal are bent into a circular arc of radius R by a perpendicular magnetic field having a magnitude B . The work function of the metal is (Where symbols have their usual meanings) -
Options
- Ahc - m _ e + e ² ~B ² R ² 2 ~m _ e
- Bhc +2 ~m _ e ( eBR 2 ~m _ e )²
- Chc - m _ c C ²- e ² ~B ² R ² 2 ~m _ e
- Dhc -2 ~m _ c ( eBR 2 ~m _ e )²
Correct answer
D. hc -2 ~m _ c ( eBR 2 ~m _ e )²
Step-by-step solution
aligned R &= mv qB V &= qBR m = eBR m _ e hc - = KE _ (Einstein photo electric equation) &= hc - KE _ &= hc - 1 2 ~m _ e ( eBR m _ e )² &= hc -2 ~m _ e ( eBR 2 ~m _ e )² aligned