# MHT-CET Physics Crash Course “Behaviour of Gas and Free Path” Class 12

## “Behaviour of Gas and Free Path” MHT-CET Class 12 Physics Crash Course | Chapter Kinetic theory of Gases and Radiation

In this session G.S. Khairnar discussed the theory and MCQ’s of “Behaviour of Gas and Free Path”. The session will be useful for all the aspirants of MHT-CET 2022. The session will be in Marathi and English.

### Behaviour of Gas and Free Path:-

Dear students we are well familiar about the properties of fluid at rest as well as in motion. Fluid possesses the properties like surface tension, viscosity etc. In this article we are going to discuss the properties of gas.

Ideal gas Equation:-

An ideal gas or a perfect gas which strictly obeys gas laws. (Such as Boyle’s law, Charles’s Law, Lussac’s Law).

According to Boyle’s law, PV = constant

& according to Charles’s law V/T = constant

Where P is pressure, V is volume, T is temperature of gas and n is number of moles of gas.

A gas which satisfies above conditions at all temperatures and pressure is called as Ideal gas.

Characteristics of Ideal gas:-

1. The size of molecules of gas is zero with no dimensions.
2. There is no force of attraction or repulsion amongst molecules of gases.

Assumptions of Kinetic theory of gases:-

1. A gas consists of large number of small particles called as molecules.
2. All molecules of same gas are identical in mass, shape and size.
3. The gas molecules are perfectly rigid spheres of very small diameters.
4. The actual volume of gas negligibly small as compared to its occupied volume.
5. The gas molecules are always in state of random motion. i.e. gas molecules are moving in all possible directions with all possible velocities.
6. Due to their random motion, gas molecules always collide with each other and with wall of container.
7. Between any two successive collisions molecules travels in a straight line with constant velocity.
8. The distance covered by molecules during the collision is called free path.
9. As the collision is perfectly elastic kinetic energy of molecules before and after collision is same.

♦ Mean free path (λ):- The average distance travelled by molecule during the collision is called mean free path.

♦ Mean velocity (C):- The mean of all velocities of gas molecules is called mean velocity.

Consider ‘N’ number of gas molecules travels with speeds C1, C2, C3…CN.

♦ Mean Square velocity (C2):- The mean of square of all velocities of gas molecules is called mean velocity.

Consider ‘N’ number of gas molecules travels with speeds C1, C2, C3…CN.

♦ Root Mean Square velocity (C2):- The square root of mean square velocity of gas molecules is called mean velocity.

### ♦जिल्हा नुसार जाहिराती ♦

अहमदनगर अकोला अमरावती औरंगाबाद भंडारा बुलढाणा
चंद्रपुर धुले गढ़चिरौली गोंदिया हिंगोली जलगांव
जालना कोल्हापुर लातूर मुंबई नागपुर नांदेड़
नंदुरबार नाशिक उस्मानाबाद पालघर परभानी पुणे
रायगढ़ रत्नागिरि सांगली सातारा सिंधुदुर्ग सोलापुर
ठाणे वर्धा वाशिम यवतमाल बीड

### ♦शिक्षणानुसार जाहिराती ♦

७ वी (7th) दहावी (SSC) बारावी (HSC) डिप्लोमा आय.टी.आय पदवी
पदव्युत्तर शिक्षण बी.एड एम.एड एल.एल.बी / एल.एल.एम बीएससी एमबीए
बीसीए एमसीए बी.कॉम एम.कॉम GNM/ANM एमएससी
बी.फार्म एम.फार्म बी.ई एम.ई BAMS/BHMS एम.बी.बी.एस / एम.डी
बी.टेक एम.टेक MS-CIT