What type of interference occurs when two crests or 2 troughs join

i think the answer would be b

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

the strength of the electric field on the point charge= n/c

the electric field is given by

e=

q=6μc= 6 x 10⁻⁶c

r=100 m

e=

e=5.4 n/c

so the electric field on the point charge= 5.4n/c