Question

6Ol prints)Given that the work function of chromium is 4.40 eV, calculate the kinetic enerey of electrons emited fom a chromium surface that is iradiated with ultraviolet radiation od wvellemgh 200 mm ( mm=10ml 7-(20 points)Drew the allowed energy for each case: (a) Free electrom Bound electiron in a square potential well with infinite potential barrier 8. (4 points) Consider a Copper metal shaped as an elongated parallelepiped. An electric field is applied to this sample in the +y direction and the magnetic field is applied in the tz direction, as schematically shown below. В. (a) Direction of Magnetic (Lorentz) Force acting on +x,-x, ty, -y,tz-z) moving electrons (Choose among (b) Direction of Internal Field (EH) set up by the deflected electrons (Choose among +x,- x, ty, -y, +z,-z) 9. (4 points) Below is the typical dependence of conductivity of ionic crystals (ceramics and glasses) on the temperature. What information can be obtained from the slope? (One sentence or one equation should be enough). log (a) 1/T 3

Answer 1

Work function, p=4.4 eV $ = 414X1.6X 1019 J d = doonm = 200x 169 m According to Einstein Photo electic equation, À the = k.€ + $ K. E = hs - % kiE= 6.625x1024x38108 - 4.481.681619 200 X 109 & K.E. = 9.9375 x lots - 7:04 x rota 3) KE = (9.9375 - 7:04) x 10ls » I KE = 2.8975 x 1019 J. O ke E. = 2.8975 x 1019 To ev 1.6x1079 I kiE:= 1.81 eV