Tag: physics

Questions Related to physics

A barometric liquid having high density produces a shorter column of liquid.

physics pressure in liquids and gases common consequences of the atmospheric pressure atmospheric pressure and its consequences important points about atmospheric pressure

  1. True

  2. False

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Correct Option: A
Explanation:

 pressure = $\rho$gh 

pressure remains constant so as $\rho$ will increase height will be shortened to get the same pressure .
so given statement is true , hence option (A) is correct

The space above the mercury column in a barometer is torricellian vacuum.

physics pressure in liquids and gases common consequences of the atmospheric pressure atmospheric pressure and its consequences important points about atmospheric pressure

  1. True

  2. False

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Correct Option: A
Explanation:

torricellian vacuum is the vaccum formed above the column of mercury in a barometer.

so opton (A) is correct

A barometer reads mercury level of $72\ cm$ at a location above sea level. If someone turns barometer  tube by $37^{o}$ with vertical, find the new reading of barometer.

physics pressure in liquids and gases common consequences of the atmospheric pressure atmospheric pressure and its consequences important points about atmospheric pressure

  1. $76\ cm$

  2. $72\ cm$

  3. $90\ cm$

  4. $68\ cm$

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Correct Option: C

The empty space above mercury in a simple barometer is called _______vaccum

physics pressure in liquids and gases common consequences of the atmospheric pressure atmospheric pressure and its consequences important points about atmospheric pressure

  1. pressure

  2. barometric

  3. torricellian

  4. mercuric

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Correct Option: C
Explanation:

Torricellian vacuum
The vacuum formed when a long tube, closed at one end and filled with mercury, is inverted into a mercury reservoir so that the open end of the tube is below the surface of the mercury. The pressure inside the Torricellian vacuum is the vapour pressure of mercury, about $103\ torr.$

The space above the mercury in a simple barometer is called 

physics pressure in liquids and gases common consequences of the atmospheric pressure atmospheric pressure and its consequences important points about atmospheric pressure

  1. Torcelian vacuum

  2. Newton's vacuum

  3. Archimede's vacuum

  4. None of these

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Correct Option: A
Explanation:

Torricellian vacuum
The vacuum formed when a long tube, closed at one end and filled with mercury, is inverted into a mercury reservoir so that the open end of the tube is below the surface of the mercury. The pressure inside the Torricellian vacuum is the vapour pressure of mercury, about 103 torr.

The moisture present in mercury ______ the barometric height of simple barometer

physics pressure in liquids and gases common consequences of the atmospheric pressure atmospheric pressure and its consequences important points about atmospheric pressure

  1. increases

  2. decreases

  3. doesn't change

  4. can't say

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Correct Option: A
Explanation:

The instrument that measures air pressure is a barometer.  There are two types of barometers, mercury and aneroid. In 1643, Toricelli invented the mercury barometer when he inserted a glass tube in a dish of mercury and observed the day-to-day variations in the height of the mercury column. When the atmospheric pressure was high, the greatest pressure was exerted on the mercury in the dish, causing the mercury in the glass tube to rise.  When the pressure was low, the mercury in the glass tube fell. The contemporary aneroid barometer employs a vacuum chamber sensitive to external pressure changes.  Contraction and expansion of the vacuum chamber, linked mechanically to an indicator needle, move the needle clockwise when the pressure rises and counter clockwise when the pressure falls.

The vertical height of mercury which a simple barometer can support at sea level is 

physics pressure in liquids and gases common consequences of the atmospheric pressure atmospheric pressure and its consequences important points about atmospheric pressure

  1. $76 cm$

  2. more than $76cm$

  3. less than $76 cm$

  4. none of these

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Correct Option: C
Explanation:

Answer is C.

The mercury level in the tube of the barometer falls until it is about $76 cm (760 mm)$ vertically above the mercury level. It is the atmospheric pressure acting on the surface of the mercury in the trough that supports the vertical mercury column.
The atmospheric pressure is therefore specified by so many millimetres of mercury. For example, the atmospheric pressure is $760 mm$ Hg at sea level.
Hence, The vertical height of mercury which a simple barometer can support at sea level is less than 76 cm. 

The purpose of a barometer is

physics pressure in liquids and gases common consequences of the atmospheric pressure atmospheric pressure and its consequences important points about atmospheric pressure

  1. To measure atmospheric temperature.

  2. To measure altitude.

  3. To measure atmospheric pressure.

  4. To measure atmospheric pollution.

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Correct Option: C
Explanation:

A barometer is an instrument that is used to measure pressure.

Barometer is used for measuring:

physics pressure in liquids and gases common consequences of the atmospheric pressure atmospheric pressure and its consequences important points about atmospheric pressure

  1. Liquid pressure

  2. Thrust

  3. Atmospheric pressure

  4. Air temp

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Correct Option: C
Explanation:

A barometer is a device used for measuring atmospheric pressure.

A classic mercury barometer is constructed from a 3-foot glass tube that is open at one end and sealed at the opposite end. The glass tube is filled with liquid mercury and rests upside-down in a reservoir of mercury. As the mercury moves down the glass tube, a vacuum is created. When the atmospheric pressure above the reservoir increases, the mercury inside the tube rises. As atmospheric pressure decreases the mercury moves down the tube, into the reservoir.The change in the mercury level in the glass tube is equal to the pressure exerted by the air above the reservoir and is measured using the scale marked on the glass tube. 

A manometer is used to measure

physics pressure in liquids and gases common consequences of the atmospheric pressure atmospheric pressure and its consequences important points about atmospheric pressure

  1. Height

  2. Pressure

  3. liquid density

  4. Atmospheric pressure

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Correct Option: B
Explanation:

A manometer is any device used to measure pressure. However, the word manometer is commonly used to mean a pressure sensor which detects pressure change by means of liquid in a tube.
Manometers are differential pressure sensors. A differential pressure sensor measures the difference between a pressure being applied to it and a reference pressure (often atmospheric pressure).