A Glass Tube Has One End in a Dish of Mercury

question 35

Multiple Choice

A glass tube has one end in a dish of mercury and the other end closed by a stopcock.The distance from the surface of the mercury to the bottom of the stopcock is 800 mm,as indicated by the meter stick shown in the drawing below.The apparatus is at 20°C,and the mercury level in the tube is the same as that in the dish.
-Which drawing best shows the approximate level of the mercury in the tube when a vacuum pump is connected to the top of the tube,the stopcock opened,the tube is evacuated,the stopcock is closed,and the pump is removed?

• A)drawing (1)
• B)drawing (2)
• C)drawing (3)
• D)drawing (4)