1
JEE Main 2023 (Online) 1st February Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

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
$$2.26\times10^{-5}~\mathrm{J}$$
2
JEE Main 2023 (Online) 31st January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
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
$145.75 \times 10^3 \mathrm{~ms}^{-1}$
3
JEE Main 2023 (Online) 31st January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Under the same load, wire A having length $5.0 \mathrm{~m}$ and cross section $2.5 \times 10^{-5} \mathrm{~m}^{2}$ stretches uniformly by the same amount as another wire B of length $6.0 \mathrm{~m}$ and a cross section of $3.0 \times 10^{-5}$ $\mathrm{m}^{2}$ stretches. The ratio of the Young's modulus of wire A to that of wire $B$ will be :
A
$1: 2$
B
$1: 4$
C
$1: 1$
D
$1: 10$
4
JEE Main 2023 (Online) 31st January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

If 1000 droplets of water of surface tension $$0.07 \mathrm{~N} / \mathrm{m}$$, having same radius $$1 \mathrm{~mm}$$ each, combine to from a single drop. In the process the released surface energy is :-

$$\left( {\mathrm{Take}\,\pi = {{22} \over 7}} \right)$$

A
$$7 .92 \times 10^{-4} \mathrm{~J}$$
B
$$7 .92 \times 10^{-6} \mathrm{~J}$$
C
$$8 .8 \times 10^{-5} \mathrm{~J}$$
D
$$9 .68 \times 10^{-4} \mathrm{~J}$$
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