A laser beam is directed at the Moon, 380,000 km from the Earth. The beam diverges at an angle of \thetaθ of 0.8 x 10-5 rad. What diameter spot, in m, will it make on the Moon?

3040 m

Explanation:

The formula to apply here is ;

d=∅*r  where

d is the diameter of the spot , ?

∅ is angle of divergence in radians, = 0.8 * 10⁻⁵rad

r is distance of Moon from Earth, =380,000 km

Applying the formula as;

d=∅*r

d= {0.8 *10⁻⁵} * 380,000 * 1000

d= 3040 m

you'd use the equation that establishes a relationship between  energy  and  wavelength, which looks like this

e=h⋅cλ, where

λ  - the wavelength of the photon; c  - the speed of light, usually given as  3⋅108m/s; h  -  planck's constant, equal to  6.626⋅10−34j s

plug the value you were given for the energy of the photon in the above equation to get the wavelength

e=h⋅cλ⇒λ=h⋅ce

λ=6.626⋅10−34js⋅3⋅108ms−1.257⋅10−24j=1.581⋅10−1m