Acamera lens (n = 1.50) is coated with a thin film of magnesium fluoride (n = 1.38) of thickness 120.0 nm. what wavelength in the visible spectrum is most weakly transmitted through the film?

 662 nm

Explanation:

given,

camera lens of n = 1.5

magnesium fluoride n = 1.38

thickness  = 120 n m = 120 × 10⁻⁹m

thickness =

wave length = 120× 10⁻⁹ × 4 × 1.38

                     = 0.662 × 10⁻⁶ m

                     = 662 nm

hence, the wavelength is equal to  662 nm

305.7

explanation:

density =m/v

density =917/3.00

density = 305.

approximately = 305.7

in four significant figures