1
JEE Main 2020 (Online) 5th September Evening Slot
MCQ (Single Correct Answer)
+4
-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)
A
r
B
r4
C
r3
D
r2
2
JEE Main 2020 (Online) 5th September Morning Slot
MCQ (Single Correct Answer)
+4
-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) :
A
1 mm
B
$${3 \over {100}}$$ mm
C
10 mm
D
$${1 \over {10}}$$ mm
3
JEE Main 2020 (Online) 5th September Morning Slot
MCQ (Single Correct Answer)
+4
-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 :
A
$${{2} \over 3}$$R
B
$${{4} \over 9}$$R
C
$${{1} \over 3}$$R
D
$${{8} \over 9}$$R
4
JEE Main 2020 (Online) 4th September Evening Slot
MCQ (Single Correct Answer)
+4
-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)
A
0.6
B
20
C
1.67
D
5
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Physics
Mechanics
Electricity
Optics
Modern Physics
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Physical Chemistry
Inorganic Chemistry
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