Question

plz solve science question​

Answer 1

Answer:

The simplest kind of barometer is a tall closed tube standing upside down in a bath of mercury (a dense liquid metal at room temperature) so the liquid rises partly up the tube a bit like it does in a thermometer. We use mercury in barometers because it's more convenient than using water. Water is less dense (less heavy, in effect) than mercury so air pressure will lift a certain volume of water much higher up a tube than the same volume of mercury. In other words, if you use water, you need a really tall tube and your barometer will be so enormous as to be impractical. But if you use mercury, you can get by with a much smaller piece of equipment.

A piece of apparatus like this is called a Torricellian barometer for Italian mathematician Evangelista Torricelli (1608–1647), a pupil of Galileo's, who invented the first instrument of this kind in 1643. He took a long glass tube, sealed at one end, filled it with mercury from a bowl, put his finger over the open end, tipped it upside down, and stood it upright in the mercury bowl. Since he was careful not to let any air into the tube, the space that formed above the mercury column was a vacuum. Indeed, this was the first time anyone had ever produced a vacuum in a laboratory (and a vacuum made this way is called a Torricellian vacuum in honor of its inventor).

At sea level, the atmosphere will push down on a pool of mercury and make it rise up in a tube to a height of approximately 760mm (roughly 30in). We call this air pressure one atmosphere (1 atm). Go up a mountain, and take your Torricellian barometer with you, and you'll find the pressure falls the higher you up go. The atmosphere no longer pushes down on the mercury quite so much so it doesn't rise so far in the tube. Maybe it'll rise to more like 65cm (25 in). The pressure on top of Mount Everest is slightly less than a third of normal atmospheric pressure at sea level (roughly 0.3 atm).

Answer 2

Explanation:

pascal law: it states that change in pressure at any region of a fluid will be transmitted equally in all direction without being diminished.

means that if pressure is applied on a body then the pressure acting on all possible direction will be same .