Silica is added to roasted copper ore during smelting in order to remove

The area (in square units) of the circle which touches the lines $4x + 3y = 15$ and $4x + 3y = 5$ is

Which of the following compounds is an optically inactive compound?

Two metal plates each of area $A$ form a parallel plate capacitor with air in between the plates. The distance between the plates is $d$. $A$ metal plate of thickness $d/2$ and of same area $A$ is inserted between the plates to form two capacitors of capacitances $C_1$ and $C_2$ as shown in the figure. If the effective capacitance of the two capacitors is $C^{\prime}$ and the capacitance of the capacitor initially is $C$,then $C^{\prime}/C$ is

The $d-$orbitals which are involved in the hybridization of the central atom in $ICl_4^{-}$ are:

Which of the following statements is correct for diamagnetic materials?