In set a, what would you have to do to the objects to make the gravitational forces between the objects in pair 2 the same as the forces between the objects in pair 1?

1 - wave length

2 - amplitude

3 - crest

4 - trough

explanation:

duh.

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.

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