An inductor coil stores $U$ energy when $i$ current is passed through it and dissipates energy at the rate of $P$. The time constant of the circuit,when this coil is connected across a battery of zero internal resistance is

The phenotype of an organism is the result of....

The chemicals and the reaction conditions required for the preparation of ethane are:

$A$ block of mass $m$ is placed on a surface with a vertical cross-section given by $y = \frac{x^3}{6}$. If the coefficient of friction is $0.5$,the maximum height above the ground at which the block can be placed without slipping is

The radii of two planets are respectively $R_1$ and $R_2$ and their densities are respectively $\rho_1$ and $\rho_2$. The ratio of the accelerations due to gravity at their surfaces is

Which of the following taxonomical aids is being described by the given statements $(i-iv)$?
$(i)$. They are generally established in educational institutes.
$(ii)$. They have collections of preserved plant and animal specimens for study and reference.
$(iii)$. Insects are preserved in boxes after collecting,killing and pinning.
$(iv)$. They often have collections of skeletons of animals too.