If the gravitational force,electromagnetic force,strong nuclear force,and weak nuclear force are represented by $GF, EMF, SNF$,and $WNF$ respectively,then which of the following represents the correct order of their relative strengths?

The dimensional formula of $\sqrt{\mu_r K}$ is equal to:

Units for constants in Column-$I$ and $SI$ unit is given in Column-$II$. Match the followings:

Column-$I$	Column-$II$
$(a)$ Wien's constant	$(i)$ $W m^{-2} K^{-4}$
$(b)$ Stefan-Boltzmann's constant	$(ii)$ $W m^{-1} K^{4}$
	$(iii)$ $m K$

Which of the following physical quantities do not have the same dimensions?

The coefficients of thermal expansion of steel and a metal $X$ are respectively $12 \times 10^{-6} /^{\circ}C$ and $2 \times 10^{-6} /^{\circ}C$. At $40^{\circ}C$,the side of a cube of metal $X$ was measured using a steel vernier callipers. The reading was $100 \, mm$. Assuming that the calibration of the vernier was done at $0^{\circ}C$,then the actual length of the side of the cube at $0^{\circ}C$ will be:

Fill in the blanks:
$(a)$ To measure the direct distance of a mountain,....... is used.
$(b)$ For the measurement of time,the ........... clock is the most accurate.
$(c)$ Rounding off $15.753$ to three significant figures gives ....... .