Ahe-ne laser produces light of 633 nm wavelength, 1.5 mw power, with a cylindrical beam of 0.64 mm in diameter.

(a) what is the intensity of this laser beam?
(b) the damage threshold of the retina is 100 w/m2 . is this laser safe to view head-on?
(c) what are the maximum values of the electric and magnetic fields?
(d) what is the average energy density in the laser beam?

Abatter hits the baseball a with an initial velocity of v0 = 110 ft/sec directly toward fielder b at an angle of 23° to the horizontal; the initial position of the ball is 2.2 ft above ground level. fielder b requires 0.44 sec to judge where the ball should be caught and begins moving to that position with constant speed. because of great experience, fielder b chooses his running speed so that he arrives at the “catch position” simultaneously with the baseball. the catch position is the field location at which the ball altitude is 8.4 ft. determine the velocity of the ball relative to the fielder at the instant the catch is made.

Light from a sodium lamp passes through a diffraction grating that has 1000 slits per millimeter. the interference pattern is viewed on a screen 1.000 m behind the grating. the first (m = 1) two bright yellow fringes that are visible are 0.7288 m and 0.7300 m from the central maximum. what are the wavelengths of these two fringes?

Most short-period comets do not have randomly oriented orbits because