Light of wavelength 180 nm ejects photoelectrons from a plate of metal whose work - function is 2 eV. If a uniform magnetic field of `5xx10^(-5)` T be applied parallel to the plate, what would be the radius of the path followed by electrons ejected normally from the plate with maximum energy.

Options

A. 0.148 m
B. 0.2 m
C. 0.25 m
D. 0.3 m

Explanation

`E=(hc)/(lambda)=6.9 eV , " " K.E_(max)=4.9 eV`
`Bqv=(mv^(2))/(r)rArrBq=(p)/(r)rArrBq=sqrt(2KEm)/(r))`
`thereforeK.E_(max)=(B^(2)q^(2)r^(2))/(2m) " " ,r=0.148m`