# Pressure vs Velocity

## Trending Questions

**Q.**If 15 g mass of nitrogen gas is enclosed in a vessel at a temperature 27∘C. Amount of heat transfered to the gas, so that rms velocity of molecules is doubled is about

[Take R=8.3 J/K mole]

- 14 kJ
- 6 kJ
- 0.9 kJ
- 10 kJ

**Q.**The mass of hydrogen molecule is 3.32×10−27 kg. If 1023 hydrogen molecules strike per second at 2 cm2 area of rigid wall of a close container normally and rebound back with the speed of 1000 m/s, then the pressure exerted on the wall (according to kinetic theory of gas) is

- 3000 N/m2
- 6640 N/m2
- 8320 N/m2
- 3320 N/m2

**Q.**

The root mean square speed of molecules of a given mass of a gas at 27^{0}C and 1 atmosphere pressure is 200 ms^{-1}. The root mean square speed of molecules of the gas at 127^{0}C and 2 atmosphere pressure is x/âˆš3 ms^{-1}. The value of x will be __________.

**Q.**An ideal gas has molar heat capacity at constant pressure Cp=5R2. The gas is kept in a cylindrical vessel fitted with a piston which is free to move. Mass of the frictionless piston is 9 kg. Initial volume of the gas is 0.0027 m3 and cross-section area of the piston is 0.09 m2. The initial temperature of the gas is 300 K. Atmospheric pressure P0=1.05×105 N/m2. An amount of 2.5×104 J of heat energy is supplied to the gas such that piston move without acceleration, then

- Initial pressure of the gas is 1.06×105 N/m2
- Work done by the gas is 1000 J
- Final pressure of the gas is 1.06×105 N/m2
- Work done by gas is 9.94×103 J

**Q.**Hydrogen gas is filled in a balloon at 20∘C. If temperature is made 40∘C, pressure remaining same, what fraction of hydrogen will come out

- 0.25
- 0.5
- 0.75
- 0.07

**Q.**The temperature of a gas is raised while keeping its volume constant. The pressure exerted by the gas on the walls of the container increases because its molecules

- lose more kinetic energy to the wall.
- gain more kinetic energy from the wall.
- strike the wall more often with higher velocities.
- strike the wall less frequently with lower velocities.

**Q.**

A cylinder of capacity 20 litres is filled with H2 gas. The total average kinetic energy of translatory motion of its molecules is 1.5Ã—105 J. The pressure of hydrogen in the cylinder is

**Q.**Gas molecules has RMS speed 200 m/s at 27∘C and 1 atm pressure. If the RMS speed changes to x√3 m/s when temperature becomes 127∘C and pressure becomes 2 atm, then the value of x is

- 100
- 200
- 300
- 400

**Q.**Each molecule of mass m of a monoatomic gas has got three degrees of freedom. The r.m.s. velocity of these atoms is v at temperature T. For a diatomic molecule of mass m and temperature T which has got five degrees of freedom, r.m.s. velocity of molecule is

- √35v
- √53v
- None of these
- v

**Q.**

He attached a small U-tube at the end of a Toricellian tube and powered in mercury from the open end (T); as mercury rose in the closed, shorter column, the trapped air would get more and move compressed - which could only mean, that the pressure increased, and the volume decreased (these were respectively measured by the height of the mercury column, h, and a scale on the shorter column, V, for volume of the trapped air).

Which of these statements is/are correct in regard to Boyle's conclusion from the data?

The height difference of the two levels is directly proportional to the pressure of the trapped air

As the value of h increased, V monotonically decreased

If we blow air through the open end of T, then h would be a bad measure for the pressure of the trapped air

The graph of h versus the reciprocal of V is a straight line

**Q.**Consider a mixture of gas molecules of type A, B and C having masses, mA<mB<mC. The ratio of their root-mean-square speeds at normal temperature and pressure is :

- vA=vB≠vC
- 1vA<1vB<1vC
- 1vA>1vB>1vC
- vA=vB=vC=0

**Q.**The density of an ideal gas is 6×10−2 kg/m3 and the root mean square velocity of the gas molecules is 500 m/s. The pressure exerted by the gas on the walls of the vessel is

- 5×103 N/m2
- 1.2×10−4 N/m2
- 0.75×10−4 N/m2
- 40 N/m2

**Q.**

A thin tube of uniform cross section is sealed at both ends. It lies horizontally, the middle 5 cm containing mercury and the parts on its two sides containing air at the same pressure P. When the tube is held at an angle of 60∘ with the vertical, the length of the air column above and below the mercury pellet are 46cm and 44.5cm respectively. Calculate the pressure P in centimeters of mercury. The temperature of the system is kept at 30∘C.

72.00 cms Hg

75.39 cms Hg

82.21 cms Hg

68.45 cms Hg

**Q.**The molecules of a given mass of gas has r.m.s speed 400 m/s at 27∘ C and 105 N/m2 pressure . When the absolute temperature is doubled and the pressure is halved, the r.m.s. speed of the molecules of the same gas is

- 400 m/s
- 200√2 m/s
- 400√2 m/s
- 1200 m/s

**Q.**

The change in the magnitude of the volume of an ideal gas when a small additional pressure $\xe2\u02c6\u2020\mathrm{P}$ is applied at a constant temperature is the same as the change when the temperature is reduced by a small quantity $\xe2\u02c6\u2020\mathrm{T}$at constant pressure. The initial temperature and pressure of the gas were $300\mathrm{K}$ and$2\mathrm{atm}$. respectively. If $\left|\xe2\u02c6\u2020\mathrm{T}\right|=\mathrm{C}\left|\xe2\u02c6\u2020\mathrm{P}\right|$then the value of C in ($\mathrm{K}{\mathrm{atm}}^{-1}$) is __________.

**Q.**The speed of a molecule of gas in a cubical vessel of side 4 m is 16 m/s. This molecule is constantly colliding with the wall of the container. The collision frequency will be

- 2 s−1
- 4 s−1
- 6 s−1
- 1 s−1

**Q.**The temperature of a gas is raised while its volume remains constant, the pressure exerted by a gas on the walls of the container increases because its molecules

- Collide with each other less frequency
- Lose more kinetic energy to the wall
- Are in contact with the wall for a shorter time
- Strike the wall more often with higher velocities

**Q.**Two containers A and B contain ideal gases, helium and oxygen respectively. Volume of both containers are equal, and pressure is also equal. Container A has twice the number of molecules than container B. If VA and VB represent the rms speed of gases in containers A and B respectively, then

- VAVB=√2
- VAVB=4
- VAVB=2
- VAVB=√8

**Q.**The average translational kinetic energy of molecules of an ideal gas is (symbols have their usual meanings)

- 12kBT
- 32kBT
- 72kBT
- 52kBT

**Q.**

Molecules of a gas behave like

Inelastic rigid sphere

Perfectly elastic non-rigid sphere

Perfectly elastic rigid sphere

Inelastic non-rigid sphere

**Q.**

Have you ever wondered what the pressure is under the glass bell jar when the vacuum pump is turned on? One way to measure it would be to see how a balloon changes when it is inside. At beginning of the experiment, you note that the volume of the balloon is 560ml under standard pressure. When you turned on the vacuum pump the balloon grows to 780ml. What is the pressure under the bell jar at this point?

**Q.**A container has an ideal gas at pressure P in thermal equilibrium. Assuming the mass of a molecule is m and all the molecules are moving wih same speed v in random directions, the expression for number of colloisions per second which the molecules make with unit area of container's wall is √xPymv. Find (x+y)

**Q.**The mass of a hydrogen molecule is 3.32×10−27 kg. If 1023 hydrogen molecules strike per second at 2 cm2 area of rigid wall of a close container normally and rebound back with the speed of 1000 m/s, then the pressure exerted on the wall (according to kinetic theory of gas) is :

- 3000 N/m2
- 6640 N/m2
- 8320 N/m2
- 3320 N/m2

**Q.**An open cylindrical tube of cross-sectional area A has two air tight frictionless pistons at its two ends. The pistons are tied with a straight piece of metallic wire. The tube contains a gas at atmospheric pressure P0 and temperature T0 in between the pistons. If temperature of the gas is doubled, then the tension in the wire is

(Assume that metallic wire is rigid)

- 4P0A
- P0A2
- P0A
- 2P0A

**Q.**

Molecules of a gas behave like

Inelastic rigid sphere

Perfectly elastic non-rigid sphere

Perfectly elastic rigid sphere

Inelastic non-rigid sphere

**Q.**The energy of a gas per litre is 300 joules, then its pressure will be

**Q.**How this relation formed

surface energy/area=surface tension?

In byju's video they derived that surface energy =Surface tension .

Please explain I am confused .

**Q.**

A box contains n molecules of a gas. How will the pressure of the gas be effected, if the number of molecules is made 2n

Pressure will decrease

Pressure will remain unchanged

Pressure will be doubled

Pressure will become three times

**Q.**For a given gas at 1 atm pressure, rms speed of the molecules is 200 m/s at 127∘ C. At 2 atm pressure and at 227∘ C, the rms speed of the molecules will be:

- 100√5 m/s
- 80 m/s
- 80√5 m/s
- 100 m/s

**Q.**Discuss the physical properties of a gas according to the postulates of kinetic theory of gases.