# Assignment 3 on heat and thermodynamics (Multiple choice type questions)

Question 1: What increase in radiated power results when the temperature of a blackbody is increased from 7 to 287 0 C
a)  4
b) 8
c) 16
d) None of these
Question 2: The internal energy of an ideal gas depends on
a) Temperature
b) Pressure
c) Volume
d) None of these
Question 3:

All Rod are of equal length and equal area of crossection.Find the temperature at point B
a,     45          b,     51.4
c,     50          d,     51
Question 4:
An ideal gas is taken through a cyclic thermodynamics process through four steps.
The amount of heat involved in the steps are Q1 = 5960 J,Q2 = - 5600 J,Q3= -3000 J,Q4 = -3600 J
respectively. The corresponding quantities of Internal energy changes are ΔU1 = 3.760 J ,ΔU2 = - 4800 J,ΔU3 = -1800 J,ΔU4 = ?
find the value ΔU4 & net work done
a, 2930 J, 960 J          b, 2830 J, 900 J
C, 2930 J, -960 J
d, -2930 J, 960 J
Question 5:
4 moles of an ideal gas undergoes an isothermal expansion at temperature T during which the volume becomes η times.
W -> Workdone by the gas
-> Change in internal energy
a)
b)
c)
d)
Q-6  M moles  of a ideal polyatomic gas(Cv=7R/2)  are in cylinder at temperature T.A heat Q is suuplied to the gas. Some M/3 moles of the gas dissociated into atoms while temperature remains constant. Find the correct relation
a) 3Q=4MRT
b) 2Q=3MRT
c) Q=4MRT
d) 7Q=4MRT
Q-7 Absorbing power of the surface is .7. Transmitting power of the surface is .1
A total heat Q is incident on the surface. Find the heat reflected back?
a)Q/6
b)Q/4
c) Q/2
d) Q/5
Q-8:
A hole of radius R1 is made centrally in a circular disc of thickness d and radius R2.The inner surface is maintained at temperature T1 and other surface is maintained at T2 (T1 > T2).Thermal conductivity of the circular plate is K.
a. Find the temperature as a function of radius from centre
b. Find the heat flow per unit time
Assertion and Reason
a) Statement I is true ,statement II is true ,statement II is correct explanation for statement I
b) Statement I is true ,statement II is true ,statement II is not a correct explanation for statement I
c) Statement I is true, Statement II is false
d) Statement I is False, Statement II is True

Q-9
STATEMENT 1:The molar specific heat capacity of the ideal gas in isothermal process is infinity
STATEMENT 2:Heat transfer is non zero in the Isothermal process

Q-10
STATEMENT 1:Equation of state for a real gas is (P+a/V2)(V-b)=nRT
STATEMENT 2: Molecular attraction is not neglible and the size of molecules are not neglibile in comparison to average separation between them

Solutions