In a torricell barometer a pressure of one atmospheric pressure supports q 760 mm coloumn of mercury. if the original tube containing the mercury is replaced with tybe having twice the diameter of the original with a tube having twice the dimaeter of the original, the height of the mercury-

The answer to the question is

The height of the mercury fluid column remain the same.

Explanation:

The pressure, P in a column of fluid of height, h is given by

P = (Density p)×(height of fluid column h)×(gravity g)

Therefore, when the diameter is doubled we have

Density of the mercury in the tube with twice the diameter = (Mass of mercury)/(volume of mercury) where the volume of mercury = h×pi×(Diameter×2)^2/4 = h×pi×Diameter^2. Therefore the volume increases by a factor of 4 and therefore the mass increases by a factor of 4 which means that the density remains the same hence

P = p×h1×g = p×h2×g Therefore h1 = h2

The height of the fluid column remain the same