If $e$ is the charge,$V$ is the potential difference,and $T$ is the temperature,then the units of $\frac{eV}{T}$ are the same as that of:

Which of the following groups has different dimensions?

The distance of a galaxy is of the order of $10^{25} \ m$. Calculate the order of magnitude of time taken by light to reach us from the galaxy.

Which of the following is the correct order of the fundamental forces in nature, arranged from weakest to strongest?

Express:
$(a)$ The energy required to break one bond in $DNA$ in $eV$.
$(b)$ The kinetic energy of an air molecule $(10^{-21} \; J)$ in $eV$.
$(c)$ The daily intake of a human adult in kilocalories.

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 $\%$)