The formula of azurite is

If $\left|\begin{array}{ccc}\cos (A+B) & -\sin (A+B) & \cos 2 B \\ \sin A & \cos A & \sin B \\ -\cos A & \sin A & \cos B\end{array}\right|=0$,then $B$ is equal to

Which gases are released when aluminum reacts with concentrated $HCl$ and concentrated $NaOH$ respectively?

Data Entry - Physics

$A$ certain mass of a gas occupies a volume of $2 \ L$ at $STP$. To what temperature must the gas be heated to double its volume,keeping the pressure constant?

$A$ convex lens has its radii of curvature equal. The focal length of the lens is $f$. If it is divided vertically into two identical plano-convex lenses by cutting it,then the focal length of the plano-convex lens is ($\mu$ = the refractive index of the material of the lens).