Tag: pressure in liquids and gases

Quizzes (11) Questions (110)

Questions Related to pressure in liquids and gases

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

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

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
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

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

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

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
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 .

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

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 $0^{o}C$. $(\alpha _{Brass}=19\times 10^{-6}/ , \gamma _{Hg}=180\times 10^{-6}/ )$ 

  1. $74.22\ cm$

  2. $77.44\ cm$

  3. $78.49\ cm$

  4. $79.94\ cm$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The apparent height of the mercury column is affected by the thermal expansion of both the mercury and the brass scale. Using the formula for corrected height H = H_obs * (1 + gamma*deltaT) / (1 + alpha*deltaT), where gamma is the expansion of mercury and alpha is the expansion of brass, the calculation yields approximately 74.22 cm.

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

When a barometer reading suddenly recedes it indicates that climate:

  1. will be very warm

  2. will be extremely stormy

  3. will remain cold

  4. incessant rain for at least $48$ hours.
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

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

  1. $76\ cm$

  2. $> 76\ cm$

  3. $< 76\ cm$

  4. Zero
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A barometer measures atmospheric pressure based on the weight of the mercury column. When an elevator accelerates upward, the effective gravity (g_eff = g + a) increases, which would normally increase the pressure reading; however, the mercury column itself also experiences this increased effective gravity, causing the height to remain constant at 76 cm.

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

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 

  1. 70 CM

  2. 72 CM

  3. 74 CM

  4. 76 CM
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In a faulty barometer with trapped air, the pressure at the mercury surface is P_atm = P_air + P_Hg. Using Boyle's law (P1V1 = P2V2) for the trapped air, where the volume is halved, the pressure of the air doubles. Solving the system of equations leads to the new reading of 70 cm.

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

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

  1. Zero

  2. $76\ cm$

  3. $> 76\ cm$

  4. $< 76\ cm.$
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

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

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

  1. 10 cm

  2. 75 cm

  3. 13.6 cm

  4. 1.36 cm
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The pressure difference between the atmosphere and the lungs supports a column of water. The pressure difference is 10 mm Hg, which is equivalent to 1 cm of Hg. Using P = h_w * d_w * g = h_Hg * d_Hg * g, the height of the water column is 13.6 cm.

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

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 $\left( \gamma _ { \mathrm { Hg } } = 18 \times 10 ^ { - 5 } / 0 \mathrm { C } \right)$

  1. $76.426 \mathrm { cm }$

  2. $75.7 \mathrm { cm }$

  3. $76.2736 \mathrm { cm }$

  4. $76.264 \mathrm { cm }$
Reveal answer Fill a bubble to check yourself
C Correct answer
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.