Calculate the energy of a photon of wavelength 11.56 meters. (planck’s constant is 6.626 x 10-34 joule seconds; the speed of light is 2.998 x 108 m/s)
5.32 x 1042 joules
2.555 x 10-41 joules second
1.718 x 10-26 joules
7.659 x 10-35 joules
1.9864 x 10-26 joules/second

Space-time metric ds2= -dt2+at2dx2+bt2dy2+ct2dz2 (a)how does the area of a rectangle with vertices at ( x=0, y=0, z=0 ), (1,0,0 ), ( 0,1,0 ) and (1,1,0 ) changes with time? (b) if a photon moving in the x direction starts from the origin at t=1, when does it reach x=l? (ds=0 for the trajectory of a photon.) (c) the proper time for a particle is defined by cd=ds. what is the proper time for a particle to move along the trajectory ( x(t)=t, y(t)=0, z(t)=0 ) from t=0 to 1 ? what is the condition on the parameter a so that the velocity of the particle never exceeds the speed of light ?

Determine the amount of work done when a crane lifts a 100-n block form 2m above the ground to 6m above the ground

Um vetor representa um deslocamento cujo módulo é 20 m. se v faz um ângulo de 60 graus com a horizontal, qual é o valor das componentes horizontal e vertical deste vetor?