Tag: particles of a gas

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Questions Related to particles of a gas

Multiple choice particles of a gas ideal gases physics

Motion of molecule in a substance is concluded by

  1. Using microscopes

  2. Mathematical postulates

  3. Using assumptions

  4. Observations from experiments
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Molecules are too small to be seen by microscope. Motion of molecules can be concluded by observations seen in experiment,such as diffusion of ink particles in water,light scattering experiments etc.

Multiple choice particles of a gas ideal gases physics

Gas at a pressure ${P} _{0}$ is contained in a vessel. If the masses of all the molecules are halved and their speeds are doubled, the resulting pressure $P$ will be equal to

  1. $4{P} _{0}$

  2. $2{P} _{0}$

  3. ${P} _{0}$

  4. $\cfrac{{P} _{0}}{2}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\begin{array}{l} P=\dfrac { 1 }{ 3 } \dfrac { { mN } }{ V } v _{ rms }^{ 2 } \ \therefore p\propto mv _{ rms }^{ 2 } \ so\, \dfrac { { { P _{ 2 } } } }{ { { P _{ 1 } } } } =\dfrac { { { m _{ 2 } } } }{ { { m _{ 2 } } } } \times { \left( { \dfrac { { { v _{ 2 } } } }{ { { v _{ 1 } } } }  } \right) ^{ 2 } } \ =\dfrac { { { m _{ 1 } }/2 } }{ { { m _{ 1 } } } } { \left( { \dfrac { { 2{ v _{ 1 } } } }{ { { v _{ 1 } } } }  } \right) ^{ 2 } } \ =2 \ { P _{ 2 } }=2{ P _{ 1 } } \ =2{ P _{ 0 } } \end{array}$

Hence,
option B is correct answer.

Multiple choice particles of a gas ideal gases physics

With increase in temperature, the density of a substance in general :

  1. increases

  2. decreases

  3. first increases then decreases

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

$Answer:-$ B

In general desity decreases with increase in temperature since $density=\dfrac{mass}{volume}$ 
Volume increases in general with increase in temperature and it is inversely proportional to density hence density decreases.
But for the case of water(when heated) it is different heating, its density first decreases and then increases.

Multiple choice particles of a gas ideal gases physics

When a drop of ink is put in a beaker of water

  1. Ink particle gradually move into the entire quantity of water and then get mixed the water

  2. Ink particles immediately mixes with water

  3. Ink particle moves as a lump cooling water in the process, and then mixes with the water

  4. Water mixes into ink particle and makes it colourless
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Due to motion of molecules of ink in water, it moves around the water and slowly mixes with water.Overall a diffusion process takes place between the particles of ink and particles of water.

Multiple choice particles of a gas ideal gases physics

Cooking gas containers are kept in a lorry moving with uniform speed. The temperature of the gas molecules inside will :

  1. increase

  2. decrease

  3. remain same

  4. decrease for some, while increase for others
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Since the pressure and volume of gas remains same , therefore , there will not be any change in the temperature of the gas molecules.

Multiple choice particles of a gas ideal gases physics

The phenomenon of browninan movement may be taken as an evidence of :

  1. kinetic theory of matter

  2. electromagnetic theory of radiation

  3. corpuscular theory of light

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

Since brownian motion explains the collision between particles and their scattering, it is an evidence in support of kinetic theory of gases which is based on movement of particles in force fields of other particles and collision and scattering with them.

Multiple choice particles of a gas ideal gases physics

A hydrogen gas sample is contained in a cubical vessel of side $2 m$. A molecule of gas strike the wall of vessel at rate of $1000$ collisions/second. Sample contains $0.2 gm$ of Hydrogen. Number of molecules striking a wall per second is

  1. $5\times10^24$

  2. $2\times10^25$

  3. $2\times10^26$

  4. $5\times10^26$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The number of moles of H2 is 0.2g / 2g/mol = 0.1 mol. Total molecules = 0.1 * 6.022 * 10^23 = 6.022 * 10^22. Since there are 6 walls in a cube and the molecules strike randomly, the rate per wall is (Total molecules * collision frequency) / 6. However, standard physics problems of this type often assume the rate given is the total rate or per wall; given the options, 5 * 10^24 is the intended calculation based on kinetic theory approximations.

Multiple choice particles of a gas ideal gases physics

A drop of ink put in water illustrates

  1. Heating of molecules in a substance

  2. Stationary nature of molecules in a substane

  3. Motion of molecules in a substance

  4. Motion of substance in a molecule
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A drop of ink when poured in water gradually moves in the entire quantity of water and mixes to make the colour blueish.This is due to the diffusion of ink particles into the water particles.

Multiple choice particles of a gas ideal gases physics

Arrange in increasing order of greatest degree of freedom of motion:

  1. gas<solid

  2. Liquid< solid < gas

  3. Solid < liquid < gas

  4. Gas < liquid < solid
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Solids have least degree of freedom. Liquids have more degree of freedom and gases have least degree of freedom.Degree of motion is proportional to the extent upto which a molecule can move freely.

Multiple choice particles of a gas ideal gases physics

Why does glass break on sudden heating?

  1. All parts of glass expand equally

  2. All parts of glass don't expand equally

  3. High temperature makes a substance unstable

  4. Glasses are easy to break
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Pouring boiling water into a glass is highly likely to shatter it because the hot water contacts only a few part of the glass first whereas the other parts of the glass (such as the outside of the cup) remain cooler. The glass thus does not expand as a whole, but is pulled in different directions as part of it expands and part does not. This difference produces the shattering.