QUESTION 29 15 points Save Answer Plutonium-239 has a half-life of 24,110 years. An initially pure sample with mass 10 kg is created in a lab. a) What mass of the sample will remain PI-239 after 100 thousand years? b) How long will it take for only 1 kg of the sample to remain PI-239?QUESTION 25 White light is incident upon a diffraction grating with 800 lines per mm. a) What is the separation between slits for this grating? b) What is the angle between the red light (700 nm) and blue light (450 nm) leaving the grating in the first order bright fringe? c) What is the angle of the second-order red light? If the angle is greater than 90 degrees, write "Not Visible". Please write your answers in the space below and email your work. For the toolbar, press ALT+F10 (PC) or ALT+FN+F10 (Mac). BIUS Paragraph Arial 10pt 2= V A V TX EE X2 X2 - ABC V V X EX: P QUESTION 26 The star Vega has a temperature of approximately 9600 K. a) What is the peak wavelength of light emitted by Vega? b) How much energy does one photon of this wavelength have? c) How much power is emitted by Vega if it has an emissivity of 0.9? (Vega has a radius of 1.64x1019 m.) d) How much mass is converted to energy every second in Vega's core to drive its power emission?QUESTION 27 15 points Save Answer Light of wavelength 22 nm is incident upon a sheet of metal of unknown type. Electrons are ejected from this metal, with a maximum kinetic energy of 10 eV (1 eV=1.6x10^-19 J ). a) What is the energy of an individual photon striking the surface of the metal? b) What is the work function of the metal? c) If the wavelength of light were shortened to 4 nm, what would the maximum kinetic energy of the emitted electrons be? Please write your answers in the space below and email your work. For the toolbar, press ALT+F10 (PC) or ALT+FN+F10 (Mac). BIUS Paragraph Arial 10pt V A V TX E ... E E X2 X2 IT The + ABC V X EX: +H P O WORDS POWERED BY TINY QUESTION 28 15 points Save Answer A thin film of oil (n=1.4) rests on the cut face of a diamond (n=2.4). Light with frequency 5.0x10^14 Hz traveling through air (n=1) is normally incident upon the oil, undergoing thin film interference. a) Will there be a relative phase shift? b) What is the wavelength of the light in the oil? c) What minimum thickness should the oil have if we wish to get constructive interference? d) What minimum thickness should the oil have if we wish to get destructive interference