Tag: introduction to atmospheric pressure

Questions Related to introduction to atmospheric pressure

2.56g of sulphur (colloidal sol) in 100 ml solution shows Osmotic pressure of 2.463 atm at ${ 27 }^{ 0 }C$. How many sulphur atoms are associated in colloidal sol ? [Solution constant = 0.0821 atm.${ mol }^{ -1 }{ k }^{ -1 }$]

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. 2

  2. 4

  3. 5

  4. 8

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Correct Option: C

The temperature of an air bubble while rising from bottom to surface of a lake remains constant but its diameter is doubled if the pressure on the surface is equal to h meter of mercury column and relative density of mercury is p then the depth of lake in metre is

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. $2\rho h$

  2. $4\rho h$

  3. $8\rho h$

  4. $7\rho h$

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Correct Option: D

The pressure of water at bottom in a lake is 3/2 times that at half depth where the water barometer reads $10$ m. The depth of the lake is:

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. $15$ m

  2. infinite

  3. $20$ m

  4. $10$ m

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Correct Option: C
Explanation:

Let the point at half depth be $x,$

$P _1=P+dgx$

Let the depth of lake be $2x$,

$P _2=P+dg2x$

$P _2=3/2×P1$

$2P _2=3P1$

$2 (P+dg2x)=3 (P+dgx)$

$2P+4dgx=3P + 3dgx$

$P=dgx$

$x=P/dg$

$x=10^5/10000 (d=10^3kg/m^3) (P=10^5pa)$

But depth of lake is $2x$

$2x=2×10=20m$

Two communicating vessels contain mercury. The diameter of one vessel is four times larger than the diameter of the other. A column of water of height $h _0=70$ cm is poured into the left hand vessel (the narrower one). How much will be mercury level rise in the right hand vessel? ( Specific density of mercury= $13.6$)

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. $0.3$ cm

  2. $0.7$ cm

  3. $0.1$ cm

  4. $1.0$ cm

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Correct Option: D

The height of mercury $(h)$ in the manometer is

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. $760\ mm$

  2. $172\ mm$

  3. $272\ mm$

  4. $300\ mm$

Show answer
Correct Option: D
Explanation:
The height of mercury (h) in the manometer is $0.30 m$
Hence,
Option $D$ is correct answer.

8 gm $O _{2}$,14 gm $N _{2}$ and 22 gm $CO _{2}$ is mixed in a container of 10 litre capacity at $27^oC$.The pressure exerted by the mixture in terms of atmospheric pressure will be-

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. 1

  2. 3

  3. 9

  4. 18

Show answer
Correct Option: C

Suppose the density of air at Hyderabad is $\rho _ { 0 }$ and atmospheric pressure is $P _ { \mathrm { atm } }$.Suppose we wish to calculate the pressure $P$ at a height $10 \mathrm { km }$ above Hyderabad. If we use the equation $P _ { 0 } - P = \rho g z$ to calculate $P$ with $z = 10 km$. But if we take only variation of $\rho$ with height we get $P _1$. if we take only of $g$ with height we get $P _2$, if we take both $\rho$ and $g$ variations with height we get $P _3$. Then 

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. $P = P _ { 1 } = P _ { 2 } = P _ { 3 }$

  2. $P _ { 3 } < P _ { 1 }$

  3. $P _ { 2 } > P$

  4. $P _ { 0 } - P > P _ { 0 } - P _ { 3 }$

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Correct Option: C

An air bubble doubles its radius on rising from the bottom of water reservoir to the surface of water in it. If the atmospheric pressure is equal to $10 m $ of water, the height of water in the reservation s- 

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. $ 10m $

  2. $20 m$

  3. $70 m$

  4. $80 m$

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Correct Option: C

A cubical block of steel each side '$\ell $' is floating in mercury in a vessel. The densities of steel and mercury are ${ p } _{ s }\quad and\quad { p } _{ m }$ .The height of block above the mercury level is given by.

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. $\ell \left( 1+\dfrac { { p } _{ s } }{ { p } _{ m } } \right) $

  2. $\ell \left( 1-\dfrac { { p } _{ s } }{ { p } _{ m } } \right) $

  3. $\ell \left( 1+\dfrac { { p } _{ m } }{ { p } _{ s } } \right) $

  4. $\ell \left( 1-\dfrac { { p } _{ m } }{ { p } _{ s } } \right) $

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Correct Option: B

A flask of volume $10^3cc$ is completely filled with mercury at $0^oC.$ The co-efficient of cubical expansion of mercury is $180\times10^{-6} /^oC$ at that of glass is $40\times10^{-6}/^oC.$ If flask is placed in boiling water at $100^oC,$ how much mercury will overflow   

physics fluid pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

  1. $7cc$

  2. $14cc$

  3. $21cc$

  4. $28cc$

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Correct Option: B