A laser beam with photons of wavelength 275 nm is incident on a surface, depositing a power of 0.407 nanoWatts on that surface. How many photons are incident on the surface during each 0.370-microsecond period

d eras and periods

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west