JEE Main 2019 (Online) 12th April Evening Slot | Properties of Matter Question 114 | Physics

JEE Main 2019 (Online) 12th April Evening Slot

MCQ (Single Correct Answer)

-1

A solid sphere, of radius R acquires a terminal velocity v₁ when falling (due to gravity) through a viscous fluid having a coefficient of viscosity . The sphere is broken into 27 identical solid spheres. If each of these spheres acquires a terminal velocity, v₂, when falling through the same fluid, the ratio (v₁/v₂) equals :

$${1 \over 9}$$

$${1 \over {27}}$$

JEE Main 2019 (Online) 12th April Evening Slot

MCQ (Single Correct Answer)

-1

The number density of molecules of a gas depends on their distance r from the origin as, $$n\left( r \right) = {n_0}{e^{ - \alpha {r^4}}}$$. Then the total number of molecules is proportional to :

$${n_0}{\alpha ^{ - 3/4}}$$

$${n_0}{\alpha ^{ - 3}}$$

$${n_0}{\alpha ^{1/4}}$$

$$\sqrt {{n_0}} {\alpha ^{1/2}}$$

JEE Main 2019 (Online) 12th April Evening Slot

MCQ (Single Correct Answer)

-1

A uniform cylindrical rod of length L and radius r, is made from a material whose Young’s modulus of Elasticity equals Y. When this rod is heated by temperature T and simultaneously subjected to a net longitudinal compressional force F, its length remains unchanged. The coefficient of volume expansion, of the material of the rod, is (nearly) equal to :

$${{3F} \over {\left( {\pi {r^2}YT} \right)}}$$

$${{6F} \over {\left( {\pi {r^2}YT} \right)}}$$

$${F \over {\left( {3\pi {r^2}YT} \right)}}$$

$${9F\left( {\pi {r^2}YT} \right)}$$

JEE Main 2019 (Online) 12th April Morning Slot

MCQ (Single Correct Answer)

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At 40^o C, a brass wire of 1 mm radius is hung from the ceiling. A small mass, M is hung from the free end of the wire. When the wire is cooled down from 40^oC to 20^oC it regains its original length of 0.2 m. The value of M is close to : (Coefficient of linear expansion and Young’s modulus of brass are 10^–5 /^oC and 10¹¹ N/m ² , respectively; g= 10 ms^–2 )

1.5 kg

0.5 kg

9 kg

0.9 kg

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