Tag: physics

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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 density of the atmosphere at sea level is 1.29 $kg/m^{2}$. assume that it does not change with altitude. then how high would the atmosphere extend?

  1. 3 km

  2. 7 km

  3. 8 km

  4. 9 km
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
We know that $p=pgh$
p is atmospheric pressure, g in acceration due to gravity
$p = 1.29 kg/m^{2} ; p-=1.013\times 10\, N/m$
$\therefore h=\dfrac{p}{pg}=\dfrac{1.013\times 10^{5}}{1.29\times 9.8}$  $= 8013 \,km$
hence atmospheric extended 8013 km high from the sea level
Multiple choice physics pressure in liquids and gases common consequences of the atmospheric pressure atmospheric pressure and its consequences important points about atmospheric pressure

we do not get crushed by the atmospheric pressure as the out internal pressure and the atmospheric pressure are?

  1. equal

  2. greater

  3. lower

  4. none of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

We don't get crushed by atmospheric pressure (about 1 kg per square cm) because our internal body pressure is equal to the atmospheric pressure. This balance of pressures prevents our bodies from collapsing. If there were a significant pressure difference, it would cause serious damage - like when divers get the bends from rapid pressure changes.

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 pressure P of a gas and its mean translational KE per unit volume are related as:

  1. $P=\dfrac{1}{2}E$
  2. $P=E$
  3. $P=\dfrac{3}{2}E$
  4. $P=(\dfrac{2}{3})E$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$\begin{array}{l} \therefore \, \, { V _{ rms } }=\sqrt { \dfrac { { 3PV } }{ M }  }  \ E=\dfrac { 1 }{ 2 } M\, \, { V _{ rms } }^{ 2 }=\dfrac { 3 }{ 2 } PV=\dfrac { 3 }{ 2 } P\, \, \left[ { \therefore \, \, V=1 } \right]  \end{array}$

Ans. (C)

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

Find the ratio of a systolic blood pressure of $120$ (in mm of Hg) to atmospheric pressure. Standard atmospheric pressure is $1.01\times 10^{5}\ Pa$

  1. 0.16

  2. 1.6

  3. 16

  4. 160
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Systolic pressure is 120 mm Hg. Convert this to Pascals: P = h * d * g = 0.12 m * 13600 kg/m^3 * 9.8 m/s^2 = 15993.6 Pa. The ratio to standard atmospheric pressure (1.01 * 10^5 Pa) is 15993.6 / 101000, which is approximately 0.158, rounding to 0.16.

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

On heating water from $0^0 C$ to $100^0 C$ its volume 

  1. Increases at each $^0 C$
  2. First increase till $4^0 C$ and then decreases
  3. First decrease till $4^0 C$ and then increases

  4. Remains same
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Water exhibits anomalous expansion. Its density is maximum at 4 degrees Celsius, meaning its volume is minimum at that temperature. Thus, as it heats from 0 to 4 degrees, it contracts (volume decreases), and from 4 to 100 degrees, it expands (volume increases).

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 volume of a given amount of water ______ when its temperature is increased form $0^0 C$ to $4^0 C$.

  1. decreases

  2. remains the same

  3. increase

  4. first increases and then decreases.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Due to the anomalous expansion of water, the volume decreases as the temperature rises from 0 degrees Celsius to 4 degrees Celsius, where it reaches its maximum density.

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 air bubble rises from bottom of a lake to surface If its radius increases by 200% and atmospheric pressure is equal to water coloumn of height H. then depth of lake is 

  1. 21H

  2. 8H

  3. 9H

  4. 26H
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let initial radius be r and final radius be r + 200% of r = 3r, meaning volume increases by 27 times. By Boyle's law (P1V1 = P2V2), the pressure at the bottom is 27 times the pressure at the surface. Since surface pressure corresponds to water column H, total pressure at depth h + H is 27H, making depth h equal to 26H.