Question

The level of mercury in the glass trough increases or decreases with the change in atmospheric pressure. Thus a permanent scale cannot be marked on the glass tube as an advantage of a barometer. type A for statement is true neither B.

Answer 1

Hint Mercury has a large core of liquid metal surrounded by a mantle of silica and a solid outer crust. In the case of Mercury, though, the core accounts for 42% of the planet, while Earth's core is only 17%.

Solution step by step Barometer is an instrument measuring atmospheric pressure, used especially in forecasting the weather and determining altitude.
A barometer is a scientific instrument used to measure atmospheric pressure, also called barometric pressure. The atmosphere is the layers of air wrapped around the Earth.
The advantages of use of mercury in a barometer are :
1. its density is very high.
2. It has low vapour pressure.
3. its rate of evaporation is not very high.
4. it neither we nor sticks to glass.
5. its surface is shining and opaque.
The disadvantages of use of mercury in a barometer are :
1. it is bulkier in nature.
2. The chances of failure of a glass tube is very high.

Advantages of a Fortin's Barometer over a simple mercury barometer:
The Fortin's barometer is an improved version of the simple mercury barometer.The barometer tube is encased in a brass frame. This enables it to be carried around easily.Vernier scale is used for taking reading for extra accuracy.

Note: This liquid form of mercury is especially dangerous because it vaporizes at room temperature. If mercury vapor is inhaled, it is easily absorbed by the body, where it first gets into the lungs and from there into the blood and the brain. The nerve poison can cause sleep disorders, agitation, and paralysis.