1
JEE Main 2013 (Offline)
MCQ (Single Correct Answer)
+4
-1
Assume that a drop of liquid evaporates by decreases in its surface energy, so that its temperature remains unchanged. What should be the minimum radius of the drop for this to be possible ? The surface tension is $$T,$$ density of liquid is $$\rho $$ and $$L$$ is its latent heat of vaporization.
A
$$\rho L/T$$
B
$$\sqrt {T/\rho L} $$
C
$$T/\rho L$$
D
$$2T/\rho L$$
2
AIEEE 2012
MCQ (Single Correct Answer)
+4
-1
Helium gas goes through a cycle $$ABCD$$ (consisting of two isochoric and isobaric lines) as shown in figure efficiency of this cycle is nearly : (Assume the gas to be close to ideal gas) AIEEE 2012 Physics - Heat and Thermodynamics Question 395 English
A
$$15.4\% $$
B
$$9.1\% $$
C
$$10.5\% $$
D
$$12.5\% $$
3
AIEEE 2012
MCQ (Single Correct Answer)
+4
-1
A wooden wheel of radius $$R$$ is made of two semicircular part (see figure). The two parts are held together by a ring made of a metal strip of cross sectional area $$S$$ and length $$L.$$ $$L$$ is slightly less than $$2\pi R.$$ To fit the ring on the wheel, it is heated so that its temperature rises by $$\Delta T$$ and it just steps over the wheel. As it cools down to surrounding temperature, it process the semicircular parts together. If the coefficient of linear expansion of the metal is $$\alpha $$, and its Young's modulus is $$Y,$$ the force that one part of the wheel applies on the other part is : AIEEE 2012 Physics - Heat and Thermodynamics Question 396 English
A
$$2\pi SY\alpha \Delta T$$
B
$$SY\alpha \Delta T$$
C
$$\pi SY\alpha \Delta T$$
D
$$2SY\alpha \Delta T$$
4
AIEEE 2012
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
A Carnot engine, whose efficiency is $$40\% $$, takes in heat from a source maintained at a temperature of $$500$$ $$K.$$ It is desired to have an engine of efficiency $$60\% .$$ Then, the intake temperature for the same exhaust (sink) temperature must be :
A
efficiency of Carnot engine cannot be made larger than $$50\% $$
B
$$1200$$ $$K$$
C
$$750$$ $$K$$
D
$$600$$ $$K$$
JEE Main Subjects
EXAM MAP