Una fuente luminosa de 75 W consume 75W de potencia electrica. Suponga que toda la energía se transforma en luz emitida de 600 nm de longitud de onda. a) Calcule la frecuencia de la luz emitida
b) ¿Cuántos fotones por segundo emite la fuente?

Unpolarized light of intensity i_0=750w/m^2 is incident upon two polarizers. after passing through both polarizers the intensity is i_2=280w/m^2. (a) what is the intensity of the light after it passes through the first polarizer in w/m^2? (b) write an equation for the angle between the polarizers in terms of the initial (i_0) and final (i_2) intensities. (c) find the angle between the polarizers in degrees.

The ima of the following pulley system is

Which temperature scale measures water boiling at 100 degrees? which temperature scale measures water boiling at 100 degrees?