Match the physical quantities in Column-$I$ with those in Column-$II$ having the same dimensions. The correct matching is:

$A$. Entropy	$I$. Angular velocity
$B$. Young's modulus of elasticity	$II$. Boltzmann constant
$C$. Angular momentum	$III$. Energy density
$D$. Decay constant	$IV$. Planck's constant

$A$ new unit $(\alpha)$ of length is chosen such that it is equal to the speed of light in vacuum. What is the distance between Venus and Earth in terms of $\alpha$ units if light takes $6 \text{ min } 40 \text{ s}$ to cover this distance (in $\text{ } \alpha$)?

The unit of "impulse per unit area" is the same as that of

Just as precise measurements are necessary in science,it is equally important to be able to make rough estimates of quantities using rudimentary ideas and common observations. Think of ways by which you can estimate the following (where an estimate is difficult to obtain,try to get an upper bound on the quantity):
$(a)$ The total mass of rain-bearing clouds over India during the Monsoon.
$(b)$ The mass of an elephant.
$(c)$ The wind speed during a storm.
$(d)$ The number of strands of hair on your head.
$(e)$ The number of air molecules in your classroom.

Which of the following quantities has a unit but is dimensionless?

Although the units of torque and work are the same,why are they not the same physical quantities?