What is the maximum mass that can hang without sinking from a 10.0- cm -diameter Styrofoam sphere in water

if you already have the answer to (a), then just work out how many periods there are in 1 minute, and that's the answer to (c).

b. latent learning (the word "latent" itself means something that exists but isn't obvious, only under certain conditions! )

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