B.Sc-B.Sc Physics 1st Sem Mechanics, Heat and Thermodynamics(University of Pune, Pune-2013)
F.Y. B.Sc.
PHYSICS - I
SEAT No. :
[Total No. of Pages : 2
Mechanics, Heat and Thermodynamics
(Paper - I) (2008 Pattern)
Time : 3 Hours] [Max. Marks : 80
Instructions to the candidates :
1) All questions are compulsory.
2) Figures to the right indicates full marks.
3) Use of log table and calculator is allowed.
4) Neat diagram must be drawn wherever necessary.
Q1) Attempt all of the following :
a) What is difference between mass and weight? [2]
b) The initial velocity of the body is 16 m/s. What is its velocity after 2.5
sec if it accelerate uniformly at 4.5 m/s2. [2]
c) Give any two applications of surface tension. [2]
d) Write the statement of Bernoulli’s theorem. [2]
e) State first law of thermodynamics. [2]
f) Calculate the coefficient of performance of Carnot’s refrigerator working
between the temperatures 127ºC and 27ºC. [2]
g) What are the advantages of mercury thermometer? [2]
h) Define isobaric and isochoric changes. [2]
Q2) Attempt any four of the following :
a) Describe the Jaeger’s method to determine surface tension of a liquid.[4]
b) What is average acceleration? Interpreat average acceleration using v - t
graph in one dimensional motion. [4]
c) What is pseudo force? Illustrate with examples. [4]
d) What force is required to accelerate 2000kg car from 10 m/s to 40 m/s in
time of 10 sec. [4]
e) Water flowing in a horizontal pipe has a speed 40cm/s at one end point
and 30cm/s at another point. Determine the pressure drop between two
points. [4]
f) A metal cube of side 6cm and relative density 8kg/m 3 is suspended by a
string so as to be completely immersed in a liquid of density 1.2 × 103
kg/m3. Find the tension in the string. [4]
P.T.O.
Q3) Attempt any four of the following
a) g times the slope of the isothermal curve through the same point. [4]
b) Show that the entropy remains constant during a reversible cyclic
change. [4]
c) What is Boyle’s temperature? Obtain the relation between Boyle
temperature and critical temperature. [4]
d) Find the temperature in Fahrenheit scale, Kelvin scale and Reaumur scale
corresponding to 45ºC. [4]
e) The expansion ratio and compression ratio are 6 and 12 respectively. If
the value ofg is 1.4 for the working substance in a Diesel engine. Find its
efficiency.
f) A reversible engine converts 1/8 th of heat into work. When temperature
of the sink is decreased by 62ºK, its efficiency is doubled. Find the
temperature of the source. [4]
Q4) Attempt any two of the following :
a) State the working principle of venturimeter and discuss in detail the
working of venturimeter. [8]
b) i) A position of particle along x - axis with time is given by x (t) = 7 +
5t + 8t2 where x in meter.
1) Find the average velocity between t = 0 and t = 1sec.
2) Find the value of acceleration at t = 0.5 and t = 1sec. [4]
ii) State the principle of conservation of energy and show that the total
mechanical energy remain constant. [4]
c) i) Calculate the work done in moving a particle along a vector
r& = (3i - j + 6k ) meter,iftheapplied forceis F =(i +3 j + 2k ) Newton. [4]
ii) Obtain the equation of continuity. [4]
Q5) Attempt any two of the following :
a) Describe Carnot’s heat engine. Obtain an expression for its efficiency.[8]
b) i) Calculate the work done when a gram molecule of a gas expands
isothermally at 37ºC to double its original volume (R = 8.3 joule/
degree/mole). [4]
ii) Derive reduced equation of state from van-der-waals equation of
state. [4]
c) i) Calculate the van-der-waal’s constant ‘a’ and ‘b’ for dry air given
that Tc = 132ºK, Pc = 37.2 atmp. and R = 82.07 cm3.atmp/ºK. [4]
ii) Explain construction and working of liquid filled thermometer. [4]
| Earning: Approval pending. |
