Find the equivalent capacitance across $A$ and $B$ in $\mu F$.

If $\cos (A-B)=3/5$ and $\tan A \tan B=2$,then which one of the following is true?

Which of the following is the chemical formula of dolomite?

The magnetic induction at the centre of a current-carrying circular coil of radius $10 \ cm$ is $5 \sqrt{5}$ times the magnetic induction at a point on its axis. The distance of the point from the centre of the coil (in $cm$) is:

The value of $x$,where $x>0$ and $\tan \left(\sec ^{-1}\left(\frac{1}{x}\right)\right)=\sin \left(\tan ^{-1} 2\right)$ is

The wavelengths of two sound notes in air are $\frac{40}{195} ~m$ and $\frac{40}{193} ~m$. Each note produces $9$ beats per second separately with a third note of fixed frequency. The velocity of sound in air in $m/s$ is