Determine the pressure difference in tube of non-uniform cross sectional area as shown in figure.

$\Delta P=?, d_1=5 \mathrm{~cm}, v_1=4 \mathrm{~m} / \mathrm{s}, d_2=2 \mathrm{~cm}, v_2=?$

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 $T=0.1 \mathrm{~N} / \mathrm{m}$.

Assertion : Water drops take spherical shape when falling freely.

Reason : Water has minimum surface tension among all liquids.

Assertion : Sometimes insects can walk on water.

Reason : The gravitational force on insect is balanced by force due surface tension.

Assertion Smaller drop of water resist deformation forces better than the larger drops.

Reason Excess pressure inside drop is inversely proportional to its radius.