Physics M.C.Q (1 Marks)

Atoms attracts when they are little distance apart and repel, if they being squeezed into one another.

Temperature of a gas is directly proportional to its kinetic energy.
Thus, energy of an ideal gas depends only on its temperature.

The measure of average kinetic energy of molecules is called temperature.

The term ideal gas refers to a hypothetical gas composed of molecules which follow a few rules:
Ideal gas molecules do not attract or repel each other.

Temperature is defined as the average kinetic energy of the molecules in a gas sample. Average is same for all the molecules of the sample. So, kinetic energy is the same for all.

Since the amount of liquid is constant, there is no vapourisation of the liquid inside the bottle. Also, since there cannot be a liquid with no vapours at all and vapourisation cannot take place in the remaining saturated part, the remaining part must be saturated with the vapours of the liquid.

c. V will change but not P.
Explanation:
The pressure on the ideal gas does not changes from initial to final position. According to the given arrangement P = Mg/ A which shows that pressure is constant. As piston and cylinder is frictionless so by ideal gas equation, PV = nRT.

Law of equipartition of energy is used to predict the specific heat of gases and solids.

Mean free path of a molecule is defined as the average distance travelled by molecules before colliding.

Assumptions of Kinetic Theory of Gases All gases are made up of molecules which are constantly and persistently moving in random directions.
The separation between the molecules is much greater than the size of molecules.
When a gas sample is kept in a container, the molecules of the sample do not exert any force on the walls of the container during the collision.
The time interval of collision between two molecules, and between a molecule and the wall is considered to be very small.
All the collisions between molecules and even between molecules and wall are considered to be elastic.
All the molecules in a certain gas sample obey Newton’s laws of motion.
If a gas sample is left for a sufficient time, it eventually comes to a steady state.
The density of molecules and the distribution of molecules are independent of position, distance and time.

The atoms of gas have the most interatomic space and can therefore travel freely. This is why they travel longer distances without colliding and are therefore said to have the maximum mean free path.

Interatomic forces are attractive in long range and repulsive in short range and negligible in gases.

Latent heat of ice is more than external latent heat of fusion.

At low pressure, the concentration of gas molecules is very low. Hence, the kinetic assumption that the size of the molecules can be neglected compared to the volume of the container applies. At high temperature, molecules move very fast. So, they tend to collide elastically and forces of interaction between the molecules minimise. This is the required idea condition.

As we know kinetic energy of molecules of a gas is a function of Temperature
So, As we decrease its temperature or say cool it, its kinetic energy gradually decrease.
At a certain point which decreasing kinetic energy it starts bonding up whit molecules and thus condensation starts.

The molecules move in all possible directions in an ideal gas at equilibrium.
Since momentum is a vector quantity for every direction of motion of the molecules, there exists an opposite direction of motion of the other.
Hence, the average momentum is zero for an ideal gas at equilibrium.

If heat is coming into a substance during a phase change, then this energy is used to break the bonds between the molecules of the substance.
An example we will use here is ice melting into water.

When two bodies at different temperatures are mixed in the calorimeter, heat flows from one body to the other due to the temperature difference. This results in change in the internal energy of the individual bodies. There is no exchange of heat with the surrounding in the calorimeter. Thus, the total internal energy of the bodies remain conserved as no external work is done on them.

Internal energy is dependent on the freedom of movement of particles.
Since in gaseous state, particles are most free to move, this state has maximum internal energy.

Real gases approach ideal gas behaviour at high temperature and low pressure because at high pressures and low temperature, molecules of gases are very close to each other.

The heat energy supplied per unit mass of a substance at its melting point to convert the state of the substance from solid to liquid is known as Latent heat of Fusion.

This model is described for an ideal gas and assumes that the particles does not interact in any other way.
It is known that the root mean square velocity of a particle is proportional to the absolute temperature Also for zero absolute temperature, the velocity is also zero.

The maximum pressure attainable above the water will be saturated vapour pressure at that temperature. Since saturated vapour pressure does not depend upon volume, both the vessels will have same pressure.

Real gases obey ideal gas laws at low pressure and high temperature because at low pressure the number of molecules per unit volume is less so attractive force between them is negligible.
At high temperature the speed of the molecules is very high so collisions becomes elastic.

The specific heat of a gas at constant pressure is the amount of heat required to raise the temperature of one mole of a gas by unit temperature at constant pressure.

According to Thomson's model of an atom, Atom as a whole is electrically neutral because the negatively charged electrons and positively charged protons are equal in magnitude and, thus, atom as a whole is electrically neutral.

As the liquid is decreasing, the liquid is vapourised.
We know that vapourisation cannot occur in saturated air and there cannot be any liquid with no vapour at all.
So, the vapour in the remaining part is unsaturated.

Average momentum of a gas sample is zero, so it does not depend upon any of these parameters.

As the vapour is injected, the pressure of the chamber increases. But when the pressure becomes equal to the saturated vapour pressure, it condenses. So, if more vapour is injected beyond the saturated vapour pressure, the vapour will condense and thus the vapour pressure will be constant.

The frame of reference is a system of geometric axis to which measurement of size, position or motion can be made. The frame of reference has falling properties.
The speed of light is constant in the frame of reference.
All the laws of Newton are valid in the frame of reference.
All the frame of reference move with constant velocity with respect to one another.

According to kinetic theory of gases the collision among molecules and the collision of molecule with the walls of container are elastic.

Pressure and Temperature are two thermodynamic parameters which are controlled by microscopic parameters of the system i.e speed of the molecules, their collision with the boundary and other molecules.
At a given temperature molecules move in a random fashion due to thermal energy. so when we move the container in a certain fashion that does mean random motion becomes a systematic motion i.e molecules are still moving in a random fashion and there is no change in motion of molecules with respect to each other and the container, hence no change in Temperature of the Gas.

As the ideal gas compress, then the mean free path becomes smaller so the number of collisions per second between the molecules and walls increases which increase the temperature of gas in turn Kinetic energy of gas molecule increases. Kinetic energy depends on temperature.

The heat energy supplied per unit mass of a substance at its melting point to convert the state of the substance from solid to liquid is known as Latent heat of Fusion.