Sunlight is composed of an enormous number of light particles. The 40m 2 sail surface of LightSail 2 receives about 4.0 x 1022 photons each second. What would be the total impulse (magnitude and direction) on the sail in one second? What would be the total impulse (magnitude and direction) on the sail in one day?

The momentum of light, as it is for particles, is exactly reversed when a photon is reflected straight back from a mirror, assuming negligible recoil of the mirror. The change in momentum is twice the photon’s incident momentum, as it is for the particles. Suppose that a beam of light has an intensity I and falls on an area A of a mirror and reflects from it. Er = I A t p = 2 ( I A t )/c   Use Newton’s second law to write an equation for the force on the mirror for time t. Use the variables along with c for the speed of light.

An electron initially at rest is accelerated across a potential difference of 8 kV. What are its wavelength, momentum, kinetic energy, and total energy? 13.8 90.68 8 518 pm ✔ keV/c keV (kinetic) XkeV (total)

An electron and an antielectron (each has mass 9.11 x 10-31 kg), each traveling at 0.6c relative to the lab frame, collide head on and annihilate, resulting in the creation of two identical photons which travel away in opposite directions. What is the frequency of each photon?

An electron is moving at 6.0 x 10^6 m/s. A photon of what wavelength would have the same (relativistic) momentum as the electron?

The Earth has an average surface temperature of 288K and the Sun has an average surface temperature of 5800K. Assume them to be black bodies. If the only radiation that either black body emitted was at it's peak wavelength how many more photons would Earth need to radiation than receive in order for the climate to be stable.

You set up a photoelectric experiment with an unknown metal to eject electrons. You use light of wavelength λ = 660 nm, which just BARELY ejects electrons from the metal. Planck s constant is either h = 6.63 x 10-34 J.s or h = 4.14 x 10-15 ev.s. a) What is the binding energy of the unknown metal in eV? eV b) You change the light source to one with a wavelength of λ = 300 nm. Using the binding energy you found in the previous step, find the maximum kinetic energy of an electron that is ejected from the metal in Joules. c) What is the stopping voltage for an electron with the kinetic energy you just found? Submit Answer