How can I solve this statement? Assume that light of a single color, rather than white light, passes through two slits 0.50 mm apart, and an interference pattern is observed on a screen 2.5 m away. If the distance from the central fringe to a first-order fringe is measured to be 3.3 mm on the screen, determine the light's wavelength (in nm).

it becomes positively charged by charging it

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