Which metal is protected by a layer of its own oxide?

The number of values of $x$ in the interval $[0, 3\pi]$ satisfying the equation $2 \sin^2 x + 5 \sin x - 3 = 0$ is

Injury to the adrenal cortex is not likely to affect the secretion of which one of the following?

Which of the following reactions will not result in the formation of carbon-carbon bonds?

$A$ vertical mass-spring system executes simple harmonic oscillations with a period of $2\,s$. $A$ quantity of this system which exhibits simple harmonic variation with a period of $1\,s$ is

If $(2, 0)$ is the vertex and the $y$-axis is the directrix of a parabola,then its focus is