Which is the major product of the following reaction?

The eccentricity of the ellipse $x^2+4y^2+2x+16y+13=0$ is

The temperature in $K$ at which $\Delta G = 0$ for a given reaction with $\Delta H = -20.5 \ kJ \ mol^{-1}$ and $\Delta S = -50.0 \ J \ K^{-1} \ mol^{-1}$ is:

If $z = x + iy$ is a complex number satisfying $\left| z + \frac{i}{2} \right|^2 = \left| z - \frac{i}{2} \right|^2$,then the locus of $z$ is

In the Bohr series of lines of the hydrogen spectrum,the third line from the red end corresponds to which one of the following inter-orbit transitions in an atom of hydrogen?

The angles of a triangle are in the ratio $3: 5: 10$. Then the ratio of the smallest side to the greatest side is: