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Some points to note

1. Isothermal Process
Pv=constant
VdP+PdV=0
-VdP/dV=P
Now Bulk Modulus= -VdP/dV
So Bi=P

PVy=constant
VydP+PyVy-1dV=0
So Ba=yP

2. if A sold sphere and a hollow sphere having same material and size are heated to same temperature and allowed to cool in the same surrounding ,it has been found that hollow sphere cools faster than solid sphere

Objective Thermodynamics question for IITJEE

1. In a given process on an ideal gas,dW>0 and dQ=0 .Then for the gas
a) Temperature will decrease
b) Temperature will increase
c) volume will decrease
d) none of above

2.A cylinder of diameter D and of thermal conductivity k is surrounded by a cylinderical shell of inner diameter D and Outer Diameter 2D made of material of thermal conductivity 2k.The effective thermal conductivity of the system is
a) 5k/3
b) 4k
c) 5k/4
d) 7k/4

3.what all is true for a adiabatic process
a) dQ=0
b) dW=-nCvdT
c) TVy-1=constant
d) all the above three

4. what is the ratio of r.m.s speed of H2 to O2
a) 4:1
b) 1:4
c) 2:1
d) 1:2

5.The coefficent of linear expansion of an inhomogenous rod changes linearly from α1 to α2 from one end to the other end of the rod.The effective coefficient of linear expansion of the rod is

a α12
b 1/2(α12)
c. √α1α2
d. (α12)

Solutions