Which two of the following five physical parameters have the same dimensions $?$
$(1)$ energy density
$(2)$ refractive index
$(3)$ dielectric constant
$(4)$ Young's modulus
$(5)$ magnetic field

The maximum percentage errors in the measurement of mass $(M)$,radius $(R)$,and angular velocity $(\omega)$ of a ring are $2 \%$,$1 \%$,and $1 \%$ respectively. Find the maximum percentage error in the measurement of its rotational kinetic energy $(K = \frac{1}{2} I \omega^{2})$. (in $\%$)

Match the following physical quantities in $LIST$-$I$ with their dimensional formulas in $LIST$-$II$:

$LIST$-$I$	$LIST$-$II$
$A$. Planck's constant	$I$. $ML^2T^{-2}$
$B$. Stopping potential	$II$. $T^{-1}$
$C$. Work function	$III$. $ML^2T^{-1}$
$D$. Threshold frequency	$IV$. $ML^2T^{-3}A^{-1}$

It is estimated that each $cm^2$ of Earth receives about $2 \text{ calorie}$ of heat energy per minute from the Sun. This is called the solar constant. The value of the solar constant in $S.I.$ units is:

Which of the following groups has different dimensions?

Fill in the blanks by suitable conversion of units:
$(a)$ $1\; kg\; m^{2}\; s^{-2} = \ldots\; g\; cm^{2}\; s^{-2}$
$(b)$ $1\; m = \ldots\; ly$
$(c)$ $3.0\; m\; s^{-2} = \ldots\; km\; h^{-2}$
$(d)$ $G = 6.67 \times 10^{-11}\; N\; m^{2}\; kg^{-2} = \ldots\; cm^{3}\; s^{-2}\; g^{-1}$