Physics

Problem

A light beam of wavelength

500 \text{ nm}

is incident on a metal having work function of

1.25 \text{ eV}

, placed in a magnetic field of intensity

B

. The electrons emitted perpendicular to the magnetic field

B

, with maximum kinetic energy are bent into circular arc of radius

30 \text{ cm}

. The value of

B

is \_\_\_\_\_\_

\times 10^{-7} \text{ T}