The equivalent capacity between terminal $$\mathrm{A}$$ and $$\mathrm{B}$$ is

Two similar coils each of radius $$\mathrm{R}$$ are lying concentrically with their planes at right angles to each other. The current flowing in them are I and 2I. The resultant magnetic field of induction at the centre will be $$\left(\mu_0=\right.$$ Permeability of vacuum)

The logic gate combination circuit shown in the figure performs the logic function of

Two sounding sources send waves at certain temperature in air of wavelength $$50 \mathrm{~cm}$$ and $$50.5 \mathrm{~cm}$$ respectively. The frequency of sources differ by $$6 \mathrm{~Hz}$$. The velocity of sound in air at same temperature is