1
JEE Main 2023 (Online) 1st February Evening Shift
+4
-1

The Young's modulus of a steel wire of length $$6 \mathrm{~m}$$ and cross-sectional area $$3 \mathrm{~mm}^{2}$$, is $$2 \times 10^{11}~\mathrm{N} / \mathrm{m}^{2}$$. The wire is suspended from its support on a given planet. A block of mass $$4 \mathrm{~kg}$$ is attached to the free end of the wire. The acceleration due to gravity on the planet is $$\frac{1}{4}$$ of its value on the earth. The elongation of wire is (Take $$g$$ on the earth $$=10 \mathrm{~m} / \mathrm{s}^{2}$$) :

A
0.1 cm
B
1 cm
C
0.1 mm
D
1 mm
2
JEE Main 2023 (Online) 1st February Morning Shift
+4
-1

The average kinetic energy of a molecule of the gas is

A
proportional to volume
B
dependent on the nature of the gas
C
proportional to absolute temperature
D
proportional to pressure
3
JEE Main 2023 (Online) 1st February Morning Shift
+4
-1

A mercury drop of radius $$10^{-3}~\mathrm{m}$$ is broken into 125 equal size droplets. Surface tension of mercury is $$0.45~\mathrm{Nm}^{-1}$$. The gain in surface energy is :

A
$$28\times10^{-5}~\mathrm{J}$$
B
$$17.5\times10^{-5}~\mathrm{J}$$
C
$$5\times10^{-5}~\mathrm{J}$$
D
$$2.26\times10^{-5}~\mathrm{J}$$
4
JEE Main 2023 (Online) 31st January Evening Shift
+4
-1
For a solid rod, the Young's modulus of elasticity is $3.2 \times 10^{11} \mathrm{Nm}^{-2}$ and density is $8 \times 10^3 \mathrm{~kg} \mathrm{~m}^{-3}$. The velocity of longitudinal wave in the rod will be.
A
$3.65 \times 10^3 \mathrm{~ms}^{-1}$
B
$6.32 \times 10^3 \mathrm{~ms}^{-1}$
C
$18.96 \times 10^3 \mathrm{~ms}^{-1}$
D
$145.75 \times 10^3 \mathrm{~ms}^{-1}$
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