1
JEE Main 2020 (Online) 9th January Evening Slot
+4
-1
A small spherical droplet of density d is floating exactly half immersed in a liquid of density $$\rho$$ and surface tension T. The radius of the droplet is (take note that the surface tension applies an upward force on the droplet) :
A
$$r = \sqrt {{T \over {\left( {d - \rho } \right)g}}}$$
B
$$r = \sqrt {{{2T} \over {3\left( {d + \rho } \right)g}}}$$
C
$$r = \sqrt {{T \over {\left( {d + \rho } \right)g}}}$$
D
$$r = \sqrt {{{3T} \over {\left( {2d - \rho } \right)g}}}$$
2
JEE Main 2020 (Online) 9th January Evening Slot
+4
-1
Two steel wires having same length are suspended from a ceiling under the same load. If the ratio of their energy stored per unit volume is 1 : 4, the ratio of their diameters is:
A
1 : 2
B
2 : 1
C
$$1:\sqrt 2$$
D
$$\sqrt 2 :1$$
3
JEE Main 2020 (Online) 9th January Morning Slot
+4
-1
Water flows in a horizontal tube (see figure).
The pressure of water changes by 700 Nm–2
between A and B where the area of cross section
are 40 cm2 and 20 cm2, respectively. Find the
rate of flow of water through the tube.
(density of water = 1000 kgm–3)
A
1810 cm3/s
B
2420 cm3/s
C
3020 cm3/s
D
2720 cm3/s
4
JEE Main 2020 (Online) 8th January Evening Slot
+4
-1
Two liquids of densities $${\rho _1}$$ an $${\rho _2}$$ ($${\rho _2}$$ = 2$${\rho _1}$$) are filled up behind a square wall of side 10 m as shown in figure. Each liquid has a height of 5 m. The ratio of the forces due to these liquids exerted on upper part MN to that at the lower part NO is (Assume that the liquids are not mixing)
A
1/3
B
1/2
C
1/4
D
2/3
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