Which of the following statements regarding the nature of physical laws is $NOT$ correct?

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

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:

The density of a solid ball is to be determined in an experiment. The diameter of the ball is measured with a screw gauge,whose pitch is $0.5 \ mm$ and there are $50$ divisions on the circular scale. The reading on the main scale is $2.5 \ mm$ and that on the circular scale is $20$ divisions. If the measured mass of the ball has a relative error of $2 \%$,the relative percentage error in the density is (in $\%$)

The related effort to derive the properties of a bigger,more complex system from the properties and interactions of its constituent simpler parts is:

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: