1
JEE Main 2020 (Online) 2nd September Evening Slot
+4
-1
A capillary tube made of glass of radius 0.15 mm is dipped vertically in a beaker filled with methylene iodide (surface tension = 0.05 Nm–1, density = 667 kg m–3) which rises to height h in the tube. It is observed that the two tangents drawn from liquid-glass interfaces (from opp. sides of the capillary) make an angle of 60o with one another. Then h is close to (g = 10 ms–2)
A
0.049 m
B
0.087 m
C
0.137 m
D
0.172 m
2
JEE Main 2020 (Online) 2nd September Morning Slot
+4
-1
A cylindrical vessel containing a liquid is rotated about its axis so that the liquid rises at its sides as shown in the figure. The radius of vessel is 5 cm and the angular speed of rotation is $$\omega$$ rad s–1. The difference in the height, h (in cm) of liquid at the centre of vessel and at the side will be :
A
$${{2{\omega ^2}} \over {25g}}$$
B
$${{5{\omega ^2}} \over {2g}}$$
C
$${{25{\omega ^2}} \over {2g}}$$
D
$${{2{\omega ^2}} \over {5g}}$$
3
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
$$r = \sqrt {{{3T} \over {\left( {2d - \rho } \right)g}}}$$
4
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
$$\sqrt 2 :1$$
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Modern Physics
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