From the ground state electronic configuration of the elements given below,pick the one with the highest value of second ionisation energy.

In an experiment,four quantities $a, b, c$ and $d$ are measured with percentage errors of $1\%, 2\%, 3\%$ and $4\%$ respectively. Quantity $P$ is calculated as $P = \frac{a^3 b^2}{cd}$. The percentage error in the measurement of $P$ is .......... $\%$

The ends of a stretched wire of length $L$ are fixed at $x = 0$ and $x = L$. In one experiment,the displacement of the wire is $y_1 = A \sin(\pi x/L) \sin(\omega t)$ and the energy is $E_1$. In another experiment,its displacement is $y_2 = A \sin(2\pi x/L) \sin(2\omega t)$ and the energy is $E_2$. Then:

If $N$ is the number of turns in a coil,the value of self-inductance varies as

$A$ person speaking normally produces a sound intensity level of $40\, dB$ at a distance of $1\, m$. If the threshold intensity level for reasonable audibility is $20\, dB$,the maximum distance at which he can be heard clearly is ..... $m$.

The bob of a simple pendulum is hanging vertically down from a fixed identical bob by means of a string of length $l$. If both bobs are charged with a charge $q$ each,what is the time period of the pendulum? (Ignore the radii of the bobs.)