JEE Main 2020 (Online) 5th September Evening Slot | Properties of Matter Question 95 | Physics

JEE Main 2020 (Online) 5th September Evening Slot

MCQ (Single Correct Answer)

-1

In an experiment to verify Stokes law, a small spherical ball of radius r and density $$\rho $$ falls under gravity through a distance h in air before entering a tank of water. If the terminal velocity of the ball inside water is same as its velocity just before entering the water surface, then the value of h is proportional to :
(ignore viscosity of air)

r⁴

r³

r²

JEE Main 2020 (Online) 5th September Morning Slot

MCQ (Single Correct Answer)

-1

Assume that the displacement(s) of air is proportional to the pressure difference ($$\Delta $$p) created by a sound wave. Displacement (s) further depends on the speed of sound (v), density of air ($$\rho $$) and the frequency (f). If $$\Delta $$p ~ 10 Pa, v ~ 300 m/s, $$\rho $$ ~ 1 kg/m³ and f ~ 1000 Hz, then s will be of the order of (take the multiplicative constant to be 1) :

1 mm

$${3 \over {100}}$$ mm

10 mm

$${1 \over {10}}$$ mm

JEE Main 2020 (Online) 5th September Morning Slot

MCQ (Single Correct Answer)

-1

A hollow spherical shell at outer radius R floats just submerged under the water surface. The inner radius of the shell is r. If the specific gravity of the shell material is $${{27} \over 8}$$ w.r.t water, the value of r is :

$${{2} \over 3}$$R

$${{4} \over 9}$$R

$${{1} \over 3}$$R

$${{8} \over 9}$$R

JEE Main 2020 (Online) 4th September Evening Slot

MCQ (Single Correct Answer)

-1

A cube of metal is subjected to a hydrostatic pressure of 4 GPa. The percentage change in the length of the side of the cube is close to :
(Given bulk modulus of metal, B = 8 $$ \times $$ 10¹⁰ Pa)

0.6

1.67

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