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) If the barometric height gradually falls, it indicates that the moisture is increasing i.e., there is a possibility of rain.

(b) If the barometric height at a height suddenly falls, it means that the pressure at that place has suddenly decreased which indicates the coming of a storm or cyclone.

(c) A gradual increase in the barometric height means that the moisture in air is decreasing. This indicates the coming of dry weather.