Physics - Modern Physics Question with Solution | TestHub

According to Einstein's photoelectric equation, the maximum kinetic energy of the ejected photoelectron is given by

$K_{\text{max}}=E-{\Phi }_0$

Substituting the given photon energy $E=10$ units, we get

$K_{\text{max}}=10-{\Phi }_0$

When an electron enters a uniform magnetic field perpendicular to its velocity, it moves in a circular path. The radius $R$ of this path is given by

$R=\frac{mv}{eB}$

The momentum $p=mv$ can be written in terms of kinetic energy as $p=\sqrt{2m{K}_{\text{max}}}$. Substituting this into the radius formula gives

$R=\frac{\sqrt{2m{K}_{\text{max}}}}{eB}$

Substituting the value of $K_{\text{max}}$, we obtain

$R=\frac{\sqrt{2m(10-{\Phi }_0)}}{eB}$

Answer: $R=\frac{\sqrt{2m(10-{\Phi }_0)}}{eB}$