The work done in rotating a dipole placed parallel to the electric field through $$180^{\circ}$$ is W. So, the work done in rotating it through $$60^{\circ}$$ is $$\left(\cos 0^{\circ}=1, \cos 60^{\circ}=\frac{1}{2}, \cos 180^{\circ}=-1\right)$$

When an electron is excited from its 4 th orbit to 5 th stationary orbit, the change in the angular momentum of electron is approximately.

(Planck's constant $$=h=6.63 \times 10^{-34} \mathrm{~J}-\mathrm{s}$$ )

The Boolean expression for the following combination is

Under the influence of force $$F_1$$ the body oscillates with a period $$T_1$$ and due to another force $$F_2$$ body oscillates with period $$T_2$$. If both forces acts simultaneously, then the resultant period is (consider displacement is same in all three cases)