1
JEE Main 2019 (Online) 9th April Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A massless spring (k = 800 N/m), attached with a mass (500 g) is completely immersed in 1 kg of water. The spring is stretched by 2 cm and released so that it starts vibrating. What would be the order of magnitude of the change in the temperature of water when the vibrations stop completely ? (Assume that the water container and spring receive negligible heat and specific heat of mass = 400 J/kg K, specific heat of water = 4184 J/kg K)
A
10–3 K
B
10–1 K
C
10–5K
D
10–4 K
2
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
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 375 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
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
$${{m{{\overline v }^2}} \over {3{k_B}}}$$

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