Cinnabar is the ore of

The normal to the curve $x = a(1 + \cos \theta)$,$y = a \sin \theta$ at $\theta$ always passes through which fixed point?

Rutherford's experiment on scattering of $\alpha-$particles showed for the first time that the atom has

Which of the following aqueous solutions will exhibit the highest boiling point?

$A$ man is watching two trains,one leaving and the other coming in with equal speeds of $4\, m/s$. If they sound their whistles,each of frequency $240\, Hz$,the number of beats heard by the man (velocity of sound in air $= 320\, m/s$) will be equal to

If $A$ is a non-zero square matrix of order $n$ with $\operatorname{det}(I+A) \neq 0$ and $A^3=O$,where $I$ and $O$ are the unit and null matrices of order $n \times n$ respectively,then $(I+A)^{-1}$ is equal to