1
JEE Main 2021 (Online) 24th February Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
The work done by a gas molecule in an isolated system is

given by, $$W = \alpha {\beta ^2}{e^{ - {{{x^2}} \over {\alpha kT}}}}$$, where x is the displacement, k is the Boltzmann constant and T is the temperature. $$\alpha$$ and $$\beta$$ are constants. Then the dimensions of $$\beta$$ will be :
A
$$[{M^0}L{T^0}]$$
B
$$[M{L^2}{T^{ - 2}}]$$
C
$$[ML{T^{ - 2}}]$$
D
$$[{M^2}L{T^2}]$$
2
JEE Main 2021 (Online) 24th February Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Two stars of masses m and 2m at a distance d rotate about their common centre of mass in free space. The period of revolution is :
A
$${1 \over {2\pi }}\sqrt {{{{d^3}} \over {3Gm}}} $$
B
$$2\pi \sqrt {{{3Gm} \over {{d^3}}}} $$
C
$${1 \over {2\pi }}\sqrt {{{3Gm} \over {{d^3}}}} $$
D
$$2\pi \sqrt {{{{d^3}} \over {3Gm}}} $$
3
JEE Main 2021 (Online) 24th February Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Two equal capacitors are first connected in series and then in parallel. The ratio of the equivalent capacities in the two cases will be :
A
4 : 1
B
1 : 2
C
2 : 1
D
1 : 4
4
JEE Main 2021 (Online) 24th February Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Moment of inertia (M. I.) of four bodies, having same mass and radius, are reported as;

I1 = M.I. of thin circular ring about its diameter,

I2 = M.I. of circular disc about an axis perpendicular to disc and going through the centre,

I3 = M.I. of solid cylinder about its axis and

I4 = M.I. of solid sphere about its diameter.

Then :
A
I1 = I2 = I3 > I4
B
I1 + I3 < I2 + I4
C
I1 = I2 = I3 < I4
D
I1 + I2 = I3 + $${5 \over 2}$$ I4
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