The excess pressure in a soap bubble is thrice that in another one. Then the ratio of their volumes is:

The potential difference $V$ and the current $i$ flowing through an instrument in an $ac$ circuit of frequency $f$ are given by $V = 5 \cos \omega t \text{ volts}$ and $i = 2 \sin \omega t \text{ amperes}$ (where $\omega = 2\pi f$). The power dissipated in the instrument is....$W$

What are the approximate weight and diameter of $Rafflesia$ $arnoldii$?

Which chemical must be applied to the roots to keep the leaves of a plant green?

Three rings,each having equal radius $R$,are placed mutually perpendicular to each other and each having its centre at the origin of the coordinate system. If current $I$ is flowing through each ring,then the magnitude of the magnetic field at the common centre is

$A$ pendulum suspended from the ceiling of a train oscillates with a time period $2\,s$,when the train is accelerating at $10\,m/s^2$. What will be its time period when the train retards at $10\,m/s^2$?