Treatment with lime can remove hardness of water caused by

The ionization energy of $He^+$ is $19.6 \times 10^{-18} \ J \ atom^{-1}$. What is the energy of the first stationary state $(n = 1)$ of $Li^{2+}$?

Fascicular,interfascicular and extra-stelar cambium together constitute:

Select the wrong statement regarding membrane channels.

If $y = \frac{3}{4} + \frac{3 \cdot 5}{4 \cdot 8} + \frac{3 \cdot 5 \cdot 7}{4 \cdot 8 \cdot 12} + \ldots \infty$,then:

$\int_{-\pi / 2}^{\pi / 2} \sin |x| \, dx$ is equal to