Physics
Mercury is preferred as a barometric liquid because :
- its density is high
- its vapour pressure is negligible
- it neither wets nor sticks to the glass
- all of the above
Answer
all of the above
Reason — Uses of mercury as a barometric liquid are —
- The density of mercury is greater than that of any liquid, so only 0.76 m of height of mercury is needed to balance the normal atmospheric pressure. Use of other liquids will require a much longer tube.
- The vapour pressure of mercury is negligible, so the vapours in the torricellian vacuum does not affect the barometric height.
- Mercury neither wets nor sticks to the glass tube, therefore it gives accurate reading.
Related Questions
At the summit of Mount Everest, the atmospheric pressure is :
- only 40% of the atmospheric pressure at sea level
- only 60% of the atmospheric pressure at sea level
- only 30% of the atmospheric pressure at sea level
- only 50% of the atmospheric pressure at sea level
At high altitudes, the atmospheric pressure is :
- less
- high
- high due to strong winds
- low due to the cloud floating above.
Which of the following properties of water is incorrect regarding its non-usage as a barometric liquid?
- It neither wets nor sticks to the glass tube
- The vapour pressure of water is high
- The surface of water cannot be easily seen while taking observations
- The density of water is low.
If the barometric height gradually falls, it indicates :
- a possibility of a storm or cyclone
- extremely dry weather
- weather will remain the same.
- a possibility of rain.