Tag: physics

Questions Related to physics

Atmospheric pressure is measured by

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

  1. Barometer

  2. Manometer

  3. Screw gauge

  4. None of these

Show answer
Correct Option: A
Explanation:

Answer is A.

A barometer is a scientific instrument used in meteorology to measure atmospheric pressure. A simple barometer consists of a long glass tube (closed at one end, open at the other) filled with mercury and turned upside down into a container of mercury. The barometer works by balancing the mercury in the glass tube against the outside air pressure, just like a set of scales. As air pressure increasesthat is, as the air becomes heavierit pushes more of the mercury up into the tube. As air pressure decreases, more of the mercury drains from the tube. So the level of mercury in the tube provides a precise measure of air pressure.

The mercury barometer was invented by:

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

  1. Celsius

  2. fahrenheit

  3. Torricelli

  4. Bernoulli

Show answer
Correct Option: C
Explanation:
  • The mercury Barometre was invented by Torricelli.
The tube in simple barometer is filled ________ with mercury.
physics pressure in liquids and gases common consequences of the atmospheric pressure atmospheric pressure and its consequences important points about atmospheric pressure

  1. Half

  2. Three-fourth

  3. Completely

  4. Two-third

Show answer
Correct Option: C
Explanation:

The tube in a simple barometer is 'completely' filled with mercury so that no air bubble is left inside the tube. 

Air creates as much pressure as created by ....... $cm$ of vertical height of mercury column in a 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. $22$

  2. $36$

  3. $76$

  4. $260$

Show answer
Correct Option: C
Explanation:

The height to which mercury rises in simple barometer is $76cm$.

This is the reason that  atmospheric pressure is often expressed as $76cm$ of Hg at sea level.

Simple barometer was first discovered in

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

  1. $1886$

  2. $1991$

  3. $1643$

  4. $1362$

Show answer
Correct Option: C
Explanation:

A mercury barometer was discovered by Torricelli in the year 1643. 

Hydraulic brakes are based on.

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

  1. Dulong and Petit's law

  2. Pascal's law

  3. Pressure law

  4. Dalton's law of partial pressure

Show answer
Correct Option: B

They does the mercury column in the barometer fall rapidly before a severe storm?

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

  1. It is due to the fall in atmospheric pressure

  2. It is due to the rise in atmospheric pressure

  3. It is due to decrease in humidity in air

  4. It is due to the severe heat energy from the sun

Show answer
Correct Option: A
Explanation:

The mercury column in the barometer fall rapidly before a severe storm, It is due to Fall in the atmospheric pressure. In general, a falling barometer indicates the approach of a storm. If the mercury is over 30.20 inches but falling quickly, warmer, cloudier weather is coming 

Hence option A is a right answer

The vertical height of the mercury column in a barometer remains unaffected even if the tube is tilted.

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

Show answer
Correct Option: A
Explanation:

Tilting of tube does not brings any change in height  as  pressure depends on height and as it is not changing. 

so given statement is true
so option (A) is correct .

The height of a barometer at a temperature of $30^{o}$ appears to be $76\ cm$ according to the brass scale which gives correct reading at $0^{o}C$. $(\alpha _{Brass}=19\times 10^{-6}/ , \gamma _{Hg}=180\times 10^{-6}/ )$ 

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

  1. $74.22\ cm$

  2. $77.44\ cm$

  3. $78.49\ cm$

  4. $79.94\ cm$

Show answer
Correct Option: A

When a barometer reading suddenly recedes it indicates that climate:

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

  1. will be very warm

  2. will be extremely stormy

  3. will remain cold

  4. incessant rain for at least $48$ hours.

Show answer
Correct Option: B
Explanation:

In summer, when the barometer falls suddenly, a thunderstorm can be expected, and if it does not rise again upon its cessation, the weather will probably continue unsettled for several days. In summer, when a thunderstorm happens, there is little or no depression of the barometer.