During the change of $O_2$ to $O_2^-$ ion,the electron adds to which one of the following orbitals?

An air column in a tube $32 ~cm$ long,closed at one end,is in resonance with a tuning fork. The air column in another tube,open at both ends,of length $66 ~cm$ is in resonance with another tuning fork. When these two tuning forks are sounded together,they produce $8$ beats per second. Then the frequencies of the two tuning forks are (Consider fundamental frequencies only):

If $\int \frac{\log \left(t+\sqrt{1+t^2}\right)}{\sqrt{1+t^2}} dt=\frac{1}{2}[g(t)]^2+c$,(where $c$ is a constant of integration),then $g(2)$ is

Steam at $100\,^{\circ}C$ is passed into $22\,g$ of water at $20\,^{\circ}C$. The mass of water that will be present when the water acquires a temperature of $90\,^{\circ}C$ (Latent heat of steam is $540\, cal/g$) is ............ $g$.

The numerical value of the charge on either plate of the capacitor $C$ shown in the figure is

Which statement is incorrect regarding predators?