A photon of energy ejects photoelectrons from tungsten

PHYSICS · Subjective · AP · Physics 2: Algebra-based · Modern Physics · Modern Physics

Problem

A photon of energy

4.9\,\text{eV}

ejects photoelectrons from tungsten. When the ejected electron enters a constant magnetic field of strength

B = 2.5\,\text{mT}

at an angle of

60^\circ

to the field direction, the maximum pitch of the helix described by the electron is

2.7\,\text{mm}

. Find the work function of the metal in electron-volts. Given that the specific charge of the electron is

1.76 \times 10^{11}\,\text{C kg}^{-1}