$Newton/meter^2$ is the unit of

It is estimated that per minute each $cm^2$ of the Earth receives about $2 \ cal$ $(1 \ cal = 4.18 \ J)$ of heat energy from the Sun. This is called the Solar constant. In $SI$ units,the value is: (in $W/m^2$)

Express $1$ atm pressure into $N/m^{2}$ and bar.

Match the items in Column-$I$ with their corresponding values in Column-$II$.

Column-$I$	Column-$II$
$(1)$ Light year	$(a)$ $3.08 \times 10^{16} \ m$
$(2)$ Parsec	$(b)$ $9.46 \times 10^{15} \ m$
$(3)$ $1 \ AU$	$(c)$ $1.496 \times 10^{11} \ m$

Which of the following is a derived unit?

Fill in the blanks:
$(a)$ $1 \, rad = \dots \text{ degrees}$
$(b)$ Light year is a unit of $\dots$
$(c)$ The solid angle subtended by a hemisphere at its center is $\dots$