Which of the following sets of atomic numbers corresponds to elements of group $16$?

Which of the following quantities does not depend upon the orbital radius of the satellite?

The angle between the tangents drawn to the parabola $y^2=4x$ from the point $(1,4)$ is

$A$ mass $M$ attached to a horizontal spring executes $S.H.M.$ of amplitude $A_1$. When the mass $M$ passes through its mean position,a smaller mass $m$ is placed over it and both of them move together with amplitude $A_2$. The ratio $\left(\frac{A_1}{A_2}\right)$ is

If $x$ is real, then the minimum value of $\frac{x^2-x+1}{x^2+x+1}$ is

$\int \frac{1+x+\sqrt{x+x^2}}{\sqrt{x}+\sqrt{1+x}} d x$ is equal to