Properties of Matter

Assertion : Sometimes insects can walk on
water.
Reason : The gravitational force on insect is
balanced by force due surface tension.

Assertion : Water drops take spherical shape
when falling freely.
Reason : Water has minimum surface
tension among all liquids.

In an isothermal process 2 water drops of radius \(1 \mathrm{~mm}\) are combined to form a bigger drop. Find the energy change in this process if \(T=0.1 \mathrm{~N} / \mathrm{m}\).

Determine the pressure difference in tube of
non-uniform cross sectional area as shown
in figure.
\(\Delta P=?, d_1=5 \mathrm{~cm}, v_1=4 \mathrm{~m} / \mathrm{s}, d_2=2 \mathrm{~cm}, v_2=?\)

If a small orifice is made at a height of
0.25 m from the ground, the horizontal
range of water stream will be

Assertion Smaller drop of water resist deformation forces better than the larger drops.
Reason Excess pressure inside drop is inversely proportional to its radius.