The resolving limit of a healthy human eye is about:

In the ground state,an element has $13$ electrons in the $M$ shell. The element is

Charges $+q$ and $-q$ are placed at points $A$ and $B$ respectively,which are at a distance $2L$ apart. $C$ is the midpoint between $A$ and $B$. The work done in moving a charge $+Q$ along the semicircle $CRD$ is:

Sertoli cells are regulated by the pituitary hormone known as:

If $\frac{x-4}{x^2-5x-2k} = \frac{2}{x-2} - \frac{1}{x+k}$,then $k$ is equal to

If $\cos x + \cos^2 x = 1$,then the value of $\sin^2 x + \sin^4 x$ is