1
JEE Main 2019 (Online) 9th April Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Two materials having coefficients of thermal conductivity '3K' and 'K' and thickness 'd' and '3d', respectively, are joined to form a slab as shown in the figure. The temperatures of the outer surfaces are '$$\theta $$2' and '$$\theta $$1' respectively, ($$\theta $$2 > $$\theta $$1). The temperature at the interface is :-

JEE Main 2019 (Online) 9th April Evening Slot Physics - Heat and Thermodynamics Question 261 English
A
$${{{\theta _1}} \over {10}} + {{9{\theta _2}} \over {10}}$$
B
$${{{\theta _2} + {\theta _1}} \over 2}$$
C
$${{{\theta _1}} \over {6}} + {{5{\theta _2}} \over {6}}$$
D
$${{{\theta _1}} \over {3}} + {{2{\theta _2}} \over {3}}$$
2
JEE Main 2019 (Online) 9th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
An HCl molecule has rotational, translational and vibrational motions. If the rms velocity of HCl molecules in its gaseous phase is $$\overline v $$ , m is its mass and kB is Boltzmann constant, then its temperature will be :
A
$${{m{{\overline v }^2}} \over {5{k_B}}}$$
B
$${{m{{\overline v }^2}} \over {6{k_B}}}$$
C
$${{m{{\overline v }^2}} \over {7{k_B}}}$$
D
$${{m{{\overline v }^2}} \over {3{k_B}}}$$
3
JEE Main 2019 (Online) 9th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Following figure shows two processes A and B for a gas. If $$\Delta $$QA and $$\Delta $$QB are the amount of heat absorbed by the system in two cases, and $$\Delta $$UA and $$\Delta $$UB are changes in internal energies, respectively, then : JEE Main 2019 (Online) 9th April Morning Slot Physics - Heat and Thermodynamics Question 265 English
A
$$\Delta $$QA > $$\Delta $$QB ; $$\Delta $$UA > $$\Delta $$UB
B
$$\Delta $$QA < $$\Delta $$QB ; $$\Delta $$UA < $$\Delta $$UB
C
$$\Delta $$QA > $$\Delta $$QB ; $$\Delta $$UA = $$\Delta $$UB
D
$$\Delta $$QA = $$\Delta $$QB ; $$\Delta $$UA = $$\Delta $$UB
4
JEE Main 2019 (Online) 9th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
For a given gas at 1 atm pressure, rms speed of the molecule is 200 m/s at 127°C. At 2 atm pressure and at 227°C, the rms speed of the molecules will be :
A
100 m/s
B
100 $$\sqrt 5 $$ m/s
C
80 $$\sqrt 5 $$ m/s
D
80 m/s
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