Advertisements
Advertisements
प्रश्न
Draw a simple diagram of a Fortin's barometer and state how it is used to measure the atmospheric pressure.
Advertisements
उत्तर
Fortin barometer is used to measure atmospheric pressure.
Before reading the Fortin barometer, the free surface of the mercury in the reservoir is made to touch the tip of the ivory pointer by raising or lowering the level with the help of the screw S2. The vernier scale is then adjusted with the screw S1 till its lower edge touches the upper meniscus of mercury in the tube. While making this adjustment the eye is kept in level with the mercury meniscus. For this adjustment, the vernier is moved till the wall of the glass plate just ceases to be visible through the slits. The vernier can read to 1/ 20 mm or 1/ 500 inch. The reading of the barometer then gives the true atmospheric pressure. A thermometer is usually provided with the barometer which is also read and correction is made for the expansion of scale with a rise in temperature and also for the change in density of mercury with temperature. The scale graduations are correct only for the temperature at which the graduations are made.
APPEARS IN
संबंधित प्रश्न
Explain why holes are made in hanging banners and hoardings.
What physical quantity is measured in torr? How is it related to the S.I. unit of the quantity?
How is the barometric height of a simple barometer affected if Its tube is pushed down into the trough of mercury?
Give two reasons why water is not a suitable barometric liquid.
Why does nose start bleeding on high mountains?
At sea level, the atmospheric pressure is 1.04 x 105 Pa. Assuming g = 10 m s-2 and density of air to be uniform and equal to 1.3 kg m-3, find the height of the atmosphere.
The atmosphere is a layer of gases surrounding the planet.
Why is it not advisable to use a fountain pen while travelling in an aeroplane?
What is meant by atmospheric pressure?
