Which one of the following halogens liberates oxygen,when passed through hot concentrated $KOH$ solution?

The solution of the differential equation $\frac{dy}{dx} = \sin(x+y) \tan(x+y) - 1$ is

The value of $k$ for which the function $f(x) = \begin{cases} (\frac{4}{5})^{\frac{\tan 4x}{\tan 5x}}, & 0 < x < \frac{\pi}{2} \\ k + \frac{2}{5}, & x = \frac{\pi}{2} \end{cases}$ is continuous at $x = \frac{\pi}{2}$ is

What type of circulatory system is present in humans?

If the electron of a hydrogen atom is present in the first orbit,the total energy of the electron is

In the circuit shown in the figure, what is the value of $I_1$ just after pressing the key $K$?