1
WB JEE 2022
+1
-0.25

27 drops of mercury coalesce to form a bigger drop. What is the relative increase in surface energy?

A
$${3 \over 2}$$
B
$${2 \over 3}$$
C
$$-$$$${2 \over 3}$$
D
8
2
WB JEE 2021
+1
-0.25
A body of density 1.2 $$\times$$ 103 kg/m3 is dropped from rest from a height 1 m into a liquid to density 2.4 $$\times$$ 103 kg/m3. Neglecting all dissipative effects, the maximum depth to which the body sinks before returning to float on the surface is
A
0.1 m
B
1 m
C
0.01 m
D
2 m
3
WB JEE 2021
+1
-0.25
Two solid spheres S1 and S2 of same uniform density fall from rest under gravity in a viscous medium and after sometime, reach terminal velocities v1 and v2, respectively. If ratio of masses $${{{m_1}} \over {{m_2}}} = 8$$, then $${{{v_1}} \over {{v_2}}}$$ will be equal to
A
2
B
4
C
$${1 \over 2}$$
D
$${1 \over 4}$$
4
WB JEE 2021
+2
-0.5
Under isothermal conditions, two soap bubbles of radii a and b coalesce to form a single bubble of radius c. If the external pressure is p, then surface tension of the bubbles is
A
$${{p({c^3} - {a^3} + {b^3})} \over {4({a^2} + {b^2} - {c^2})}}$$
B
$${{p({c^3} - {a^3} - {b^3})} \over {4({a^2} + {b^2} - {c^2})}}$$
C
$${{p({c^2} + {a^3} - {b^2})} \over {4({a^3} + {b^3} - {c^3})}}$$
D
$${{p({a^3} + {b^3} - {c^3})} \over {4({a^2} + {b^2} - {c^2})}}$$
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