What is the magnifying power for a person whose near point is at 25 cm if the focal length of the eyepiece is 50 mm

Asubmarine has a "crush depth" (that is, the depth at which water pressure will crush the submarine) of 250 m. what is the approximate pressure (water plus atmospheric) at this depth? (recall that the density of seawater is 1025 kg/m3, g = 9.81 m/s2, and 1 kg/(ms2) = 1 pa = 9.8692 10-6 atm.) a. 34.8 atm b. 24.8 atm c. 25.8 atm d. 7.8 atm

How does the amount of energy required to hold each proton and neutron in the nucleus compare to the energy released when they are removed?

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.