If $F_1, F_2$, and $F_3$ are the relative strengths of the gravitational, the weak nuclear, and the electromagnetic forces respectively, then

In the context of accuracy of measurement and significant figures in expressing results of experiment,which of the following is/are correct?
$(1)$ Out of the two measurements $50.14 \, cm$ and $0.00025 \, A$,the first one has greater accuracy.
$(2)$ If one travels $478 \, km$ by rail and $397 \, m$ by road,the total distance travelled is $478 \, km$.

The quantities which have the same dimensions as those of solid angle are:

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 $\%$)

Identify the pair that has the same dimensions.

If the percentage errors in measuring the length and the diameter of a wire are $0.1 \%$ each,the percentage error in measuring its resistance will be: (in $\%$)