Chapter 7.2 of Jingzhou 20 14 Physics "Learning in Jingzhou" is the answer ~ ~ Thank you ~ ~ ~ There are questions and answers below.

When the submarine is on the water, buoyancy is equal to gravity: F float =G, that is, ρgV row =mg, V row =

1.66× 107 kg

103kg/m3

= 1.66× 104 m3；

Similarly, the total volume of nuclear submarines: V total =

1.87× 107 kg

103kg/m3

= 1.87× 104 m3；

Therefore, the exposure volume is: V dew =V total -V row =1.87×104m3-1.66×104m3 = 2.1×103m3.

So the answer is: (1) ultrasound; Electromagnetic; (2) 1.87× 108n； (3)2. 1× 103m3。