Alaser is used in eye surgery to weld a detached retina back into place. the wavelength of the laser beam is 537 nm, while the power is 2.0 w. during surgery, the laser beam is turned on for 0.050 s. during this time, how many photons are emitted by the laser?

No. of photons, n =

Given:

wavelength of laser beam,

Power of the beam, P = 2.0 W

Time, t = 0.050 s

Solution:

Now the energy associated with the beam, is given by:

                (1)

where,

h =

c =

Now, using eqn (1)

Now, for total energy, E' calculation from the given power:

E' =

E' =

To calculate  the no. of photons, n:

n =

n =

n =

Therefore, the no. of photons emitted by the laser beam:

n =

the journeys of marquette, joliet and la salle a) new france expand.

all three of these explorers explored the midwest and the area around the great lakes, which they subsequently claimed for france.

this was a big portion of territory and expanded new france which before then only consisted of quebec province in northeastern canada

friction

explanation:

they us to move forward and backwards