Mr. li was doing a torrecelli experiment to study atmospheric pressure when the glass tube was so thin that it closed off a portion of the air when the mercury was poured. If the mercury column is only 20 cm high, the following statement is true: A. When the glass tube is placed vertically upward, the air pressure enclosed in the tube is equal to the pressure outside B. When the glass tube is placed horizontally, the air pressure enclosed in the tube is equal to the pressure outside C. When the glass nozzle is placed vertically downward (the watermark is not poured out), the air pressure enclosed in the pipe is equal to the atmospheric pressure outside D. Regardless of placement, the closed air pressure inside the tube is equal to the atmospheric pressure outside Please elaborate on why, which is right and why others are wrong Be sure to analyze them one by one

Mr. li was doing a torrecelli experiment to study atmospheric pressure when the glass tube was so thin that it closed off a portion of the air when the mercury was poured. If the mercury column is only 20 cm high, the following statement is true: A. When the glass tube is placed vertically upward, the air pressure enclosed in the tube is equal to the pressure outside B. When the glass tube is placed horizontally, the air pressure enclosed in the tube is equal to the pressure outside C. When the glass nozzle is placed vertically downward (the watermark is not poured out), the air pressure enclosed in the pipe is equal to the atmospheric pressure outside D. Regardless of placement, the closed air pressure inside the tube is equal to the atmospheric pressure outside Please elaborate on why, which is right and why others are wrong Be sure to analyze them one by one

A, P outside +20cmhg=P inside
B. Correct
C, P outside = P inside +20 cm hg
D. Say no more

A 30 cm×30 cm rectangular glass container was filled with water. Now, a portion of the water was poured into an iron bucket with a square bottom and a height of 10 cm. When the iron bucket was filled with water, the water in the container dropped by 20 cm. How long was the bottom of the iron bucket? A 30cm×30cm rectangular glass container is filled with water. Now, pour some water into an iron bucket with a square bottom and a height of 10cm. When the iron bucket is filled with water, the water surface in the container drops by 20cm. What is the side length of the bottom of the iron bucket? A 30cm×30cm rectangular glass container is filled with water. Now, pour some water into an iron drum with a square bottom and a height of 10cm. When the iron drum is filled with water, the water surface in the container drops by 20cm. What is the length of the bottom side of the iron drum?

If the length of the bottom side of the square iron bucket is x,
10 X 2=30 x 30 x 20,
X2=1800,
Solution x=30
2(Cm).
Answer: The bottom side length of a square iron bucket is 30
2 Cm.

If the side length of the bottom surface of the square iron bucket is x,
10 X 2=30 x 30 x 20,
X2=1800,
Solution x=30
2(Cm).
Answer: The bottom side length of a square iron bucket is 30
2 Cm.