Tag: common consequences of the atmospheric pressure

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


when an air particle speeds up, it actually pushes            . Complete the sentence

  1. Less

  2. More

  3. Inside

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

According to Bernoulli's theorem        $ P + \rho gh+ \dfrac{1}{2}\rho v^2= constant$
$\implies$  When $v$ is more, then pressure $(P)$ is less.
Thus when an air particle speeds up, it actually pushes less.

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

wherever the air pressure is higher, there will be a stronger force or push against an object. Is the statement True or False

  1. True

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

Pressure      $P = \dfrac{F}{A}$                $\implies P \propto F$

Thus greater the pressure, stronger will be the force.

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

The ordinary pressure of air surrounding us is

  1. 15 pounds

  2. 16 pounds

  3. 14.2 pounds

  4. 14.7 pounds
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$Answer:-$ D

The ordinary pressure of the air surrounding us is 14.7 pounds per square inch, but the pressure can change when the wind blows or an object, like a car or airplane, accelerates.

One important principle to remember is that wherever the air pressure is higher, there will be a stronger force or push against an object. It’s also helpful to know that when an air particle speeds up, it actually “pushes” less. Imagine that fast-moving air particles are in so much of a hurry that they don’t have time to apply force. This principle is used in airplane wings to make planes fly. When a plane moves along the runway, the air above the wing speeds up more, lowering the pressure, so that the air below the wing can push the plane upward.

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

What is the mass of $2$ litres of nitrogen at $22.4$ atmospheric pressure and $273\ K$ 

  1. $28\ g$

  2. $14 \times 22.4 g$

  3. $56\ g$

  4. $none\ of\ these$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Consider STP conditions:
 
1) 1 mol = 22.4 L of gas; 1 mol of Nitrogen gas = 14 g
 
2) Therefore, 22.4 L Nitrogen gas = 14 g → 2 L Nitrogen = 1.25 g
 

3) This is at a standard pressure of 1 atm. So, 22.4 atm pressure corresponds to 22.4 × 1.25 = 28 g  

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

A sphere floats in water just submerged as shown in the diagram. If atmospheric pressure is neglected

  1. Force exerted by liquid on lower half of sphere is $\dfrac{4\rho\pi\ R^{2}}{3}g$

  2. Force exerted by liquid on lower half of sphere and upper half of sphere is same in magnitude

  3. Ratio of magnitude of forces exerted by liquid on lower and upper half of sphere is $5:1$

  4. Ratio of magnitude of forces exerted by liquid on lower and upper half of sphere is $4:1$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For a sphere just submerged, the pressure varies with depth. The force on the lower half is greater than the force on the upper half due to the hydrostatic pressure gradient, resulting in a ratio of 5:1.

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

A barometer tube, containing mercury, is lowered in a vessel containing mercury until only $50 cm$ of the tube is above the level of mercury in the vessel. If the atmospheric pressure is $75 cm$ of mercury, what is the pressure at the top of the tube

  1. $33.3 kPa$

  2. $66.7kPa$

  3. $3.33 MPa$

  4. $6.67 MPa$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Since the mercury rises only $50cm$ it implies the rest of the excess atmospheric pressure is being countered by the pressure at the top of the tube.
So pressure at top=atmospheric pressure - $50cm$ of Hg=$(75-50)cm=25cm$ of Hg=$1/3\times 100kPa= 33.33kPa$