What is the kinetic energy of an electron that passes undeviated through perpendicular electric and magnetic fields if E = 4.0 kV/m and B = 8.0 mT? 1.4 eV 0.65 eV O 0.54 eV 0.84 eV O 0.71 eV

How many photons are emitted per second from a semiconductor laser which emits 0.75 mW of light at a wavelength of 540 nm? O 239E+15 O 2.04E+15 O 2.85E+15 O 3.21E+15

Electrons enter a magnetic field traveling at v, = vỹ. The constant, uniform magnetic field B = 0.75 2 T acts as a filter curving the electrons to a small gap that only allows specific electron energies. The source of electrons enters the filter as a beam that is 15 micrometers in diameter and have a range of energies from 5-25 meV. The filter redirects the beam, as pictured, to the right v = và but does not speed them up. If the filter is to further narrow the range of energies from 5-25 meV to 10-12 meV, find the dimensions of the gap. In the picture, calculate ymin and ymer, both of which can be assumed to be equal to the radius of the paths taken within the magnetic field. %3D The beam being focused to 15 um at the start can be assumed to be a point source and take circular paths within the magnetic field. Outgoing "Filtered" Electrons Blocked Electrons -不: Y Vma Incoming Electrons