In the days before scuba gear, some divers descended to underwater depths in diving bells, which are basically just upside-down containers whose open ends face down. The bell allows the person inside to breathe the air trapped inside it, observe underwater objects and marine life, and work under the water. Required:
a. If the bell is submerged to a depth of 30m below sea level, what is the water pressure at the air-water interface inside the bell?
b. If the air pressure inside the bell before submersion into the water was 1 atm (101.825 kPa), what air pressure does the person experience at that depth?

"" would be the pressure outside the bell .as well as the air pressure inside it. A further explanation is below.

According to the question,

Depth,

Pressure,

Now,

→ The water pressure outside the bell will be:

=

By putting the values, we get

=

=

And inside the air pressure will be same as the water pressure.

Thus the response above is right.

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a)  P = 4.03 10⁵ Pa, b)  P = 4.03 10⁵ Pa

Explanation:

a) The pressure as a function of the depth of a fluid is

          P = + ρ g y

where Patm is the atmospheric pressure, the sea density of about 1025 kg / m³

let's calculate

         P = 1.01825 10⁵ + 1025 9.8 30

         P = 4.03 10⁵ Pa

b) When the hood is submerged, the water exerts a perpendicular force on the entire surface, in the equilibrium position, the air is compressed by this force until the pressure it exerts is equal to the external pressure (open at the lower), therefore the air pressure is

        P = 4.03 105 Pa

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.