Tag: atmospheric pressure and its consequences

Questions Related to atmospheric pressure and its consequences

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. $79.94\ cm$

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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.

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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.

A barometer kept in an elevator reads $76\ cm$ when it is at rest. If the elevator goes up with some acceleration, the reading will be

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. $> 76\ cm$

  3. $< 76\ cm$

  4. Zero

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Correct Option: A

The reading of a barometer containing some air above the mercury column is 73cm while that of a correct one is 76 cm. If the tube of the faulty barometer is pushed down into mercury until volume of air in it is reduced to half, the reading shown by it will be 

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

  1. 70 CM

  2. 72 CM

  3. 74 CM

  4. 76 CM

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Correct Option: A

To construct a barometer, a tube of length $1 m$ filled completely with mercury and is inverted in a mercury cup. The barometer reading on a particular day is $76\ cm$. Suppose a $1 m$ tube is filled with mercury up to $76\ cm$ and then closed by a cork. It is inverted in a mercury column in the tube over the surface in the cup will be

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

  1. Zero

  2. $76\ cm$

  3. $> 76\ cm$

  4. $< 76\ cm.$

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Correct Option: D
Explanation:

The tube contains air $($because it is not fully filled$).$ This air pressure against atmosphere pressure$,$ 

therefore$,$ height of column $<76cm$ 
Hence,
option $(D)$ is correct answer.

By sucking through a straw, a student can reduce the pressure in his lungs to 750 mm of Hg (density = 13.6 gm/ $cm^3$). Using the straw, he can drink water from a glass up to a maximum depth of

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

  1. 10 cm

  2. 75 cm

  3. 13.6 cm

  4. 1.36 cm

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Correct Option: C

Brass scale of a Barometer gives correct reading at  $0 ^ { \circ } \mathrm { C } .$  coefficient of linear expansion of brass is  $18 \times 10 ^ { - 6 } / ^ { - 6 } \mathrm { C } .$  If the barometer reads  $76\mathrm { cm } $ at   $20 ^ { \circ } \mathrm { C } ,$  the correct reading is $\left( \gamma _ { \mathrm { Hg } } = 18 \times 10 ^ { - 5 } / 0 \mathrm { C } \right)$

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

  1. $76.426 \mathrm { cm }$

  2. $75.7 \mathrm { cm }$

  3. $76.2736 \mathrm { cm }$

  4. $76.264 \mathrm { cm }$

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Correct Option: C
Explanation:

$L _0=75$cm

$\begin{array}{l} a=18\times { 10^{ -6 } }{ /^{ 0 } }C \ \Delta T=20-0={ 27^{ 0 } }C \end{array}$
We know that the formula for the coefficient of linear expansion
$\begin{array}{l} L={ L _{ 0 } }\left( { 1+\alpha \Delta T } \right)  \ L=76\left( { 1+18\times { { 10 }^{ -6 } }\times 20 } \right)  \ =76\left( { 1+0.00036 } \right)  \ =76\times 1.00036 \ =76.2736 \end{array}$
Atmospheric pressure at $20^0C$ is $76.2736$ cm of brass.

A barometer kept in a stationary elevator reads $76 \mathrm { cm } ,$ If the elevator starts accelerating up the reading willbe 

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

  1. Zero

  2. equal to 76$\mathrm { cm }$

  3. more than 76$\mathrm { cm }$

  4. less than 76$\mathrm { cm }$

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Correct Option: D

State whether true or false:

A simple barometer is compact and portable. 

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: B
Explanation:

FALSE
A simple barometer is neither portable nor compact. Thus, it cannot be carried from one place to other.
Since the apparatus is made up of glass, so there is also a chance of breaking.

State whether true or false:

The air pressure can support $13.10 m$ vertical column of mercury. 

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: B
Explanation:

$P = \rho gh$, where
$P = $air pressure $= 101325Pa$
$\rho = $density of mercury$ = 13594kg/{m}^{3}$
$\implies h = 0.76m$

It can support 0.76 m vertical column of mercury.
Hence the given statement is false.