The surface of a metal is illuminated with light of $400\, nm$. The maximum kinetic energy of the ejected photoelectrons was found to be $1.68\, eV$. The work function of the metal is.......$eV$ $(hc = 1240\, eV\, nm)$.

$3.2$ moles of hydrogen iodide were heated in a sealed bulb at $444 \, ^oC$ until the equilibrium state was reached. Its degree of dissociation at this temperature was found to be $22 \%$. The number of moles of hydrogen iodide present at equilibrium are:

$A$ convex mirror of focal length $f$ forms an image which is $1/n$ times the object. The distance of the object from the mirror is

Filiform apparatus is a characteristic feature of

If the normal to the curve $y=f(x)$ at the point $(3,4)$ makes an angle of $\frac{3 \pi}{4}$ with the positive $X$-axis,then the value of $f^{\prime}(3)$ is

$A$ liquid does not wet the solid surface if the angle of contact is