The solution of the equation $\cos^2 \theta + \sin \theta + 1 = 0$ lies in the interval

In the given circuit,find the equivalent resistance between points $a$ and the combination of $b$ and $c$ (where $b$ and $c$ are connected together).

The energy levels of the hydrogen spectrum are shown in the figure. There are some transitions $A, B, C, D$ and $E$. Transitions $A, B$ and $C$ respectively represent:

As an electron makes a transition from an excited state to the ground state of a hydrogen-like atom/ion:

The slopes of the focal chords of the parabola $y^2=32x$,which are tangents to the circle $x^2+y^2=4$,are

At higher altitude,the boiling point of water is $95\,^{\circ}C$. The amount of $NaCl$ added to $1\, kg$ of water $(K_b = 0.52\, K\, kg\, mol^{-1})$ in order to raise the boiling point of the solution to $100\,^{\circ}C$ (assuming $90\%$ ionization of $NaCl$) is ........... $g$.