What do the following indicate in a barometer regarding weather :
(a) gradual fall in the mercury level,
(b) sudden fall in the mercury level,
(c ) gradual rise in the mercury level ?

A sudden drop in the mercury level by 10 mm or more is a sign of

A cup contains some mercury in it. Now a narrow glass tube is lowered in the mercury. After some time the mercury level in the tube becomes lower than the mercury level outside the tube as shown in diagram. During this process (Choose correct statements)

Comment on the experimental setup. (a) What does the setup demonstrate ? (b) What will happen to the level of water if a blower is placed close to setup ? (c) Will the mercury level fluctuate (go up/down) if phenyl mercuric acetate is sprayed on leaves ?

Two communicating vessels contain mercury. The diameter of one vessel in n times larger then the diameter of the other. A column of water of height h is poured into the left vessel. The mercury level will rise in the right hand vessel (s = relative density of mercury and rho = density of water) by

Two communicating cylindrical tubes contain mercury. The diameter of one vessel is four times large than the diameter of the outer. A column of water of height 70 cm is poured into the narrow vessel. How much wil the mercury level rise in the other vessel and how much will it sink in the narow one? How much will the mercury level rise in the narrow vessel, if a column of water of the same height is pured into the broad vessel?

Arrange the following substances in order of their increasing density : (a) iron (b) cork (c) brass (d) water (e) mercury.

A quantity of gas is collected in a gradutated tube over the mercury. The volume of the gas at 20^(@)C is 50.0 mL and the level of the mercury in the tube is 100 mm above the outside mercury level. The barometer reads 750 mm . Volume at STP is

Explain why does the mercury level in a barometer go down when atmospheric pressure decreases?

A quantity of gas is collected in a graduated tube over the mercury. The volume of gas at 18^(@)C is 50 mL and the level of mercuty in the tube is 100mm above the outside mercuty level. The barometer reads 750 torr. Hence, volume of gas 1 atm and 0^(@)C is approximately:

Mercury is poured into a U-tube in which the cross-sectional area of the left-hand limb is three times smaller than that of the right one. The level of the mercury in the narrow limb is a distandce l=30 cm from the upper end of the tube. How much will the mercury level rise in the right-hand limb if the left one is filled to the top with water?