Afive-milliwatt laser, emitting light with wavelength 690 nm is turned on for 20 seconds. we will approximate the beam as a cylinder of area 2.5 mm2 calculate the following beam quantities: a. length b. volume c. intensity d. energy e. energy density f. rms electric field g. rms magnetic field h. the number of photons (h 6.63 x 10-34 joules seconds.

Awelder using a tank of volume 7.50×10^-2 m^3 fills it with oxygen (with a molar mass of 32.0 g/mol ) at a gauge pressure of 3.30×10^5 pa and temperature of 37.1 ∘c. the tank has a small leak, and in time some of the oxygen leaks out. on a day when the temperature is 23.1 ∘c, the gauge pressure of the oxygen in the tank is 2.00×10^5 pa . a) find the initial mass of oxygen. b) find the mass of oxygen that has leaked out.