$A$ motor boat is travelling with a speed of $3.0 \, m/s$. If the force on it due to water flow is $500 \, N$,the power of the boat is:

$A$ transverse harmonic wave on a string is described by $y = 3 \sin(36t + 0.018x + \frac{\pi}{4})$,where $x$ and $y$ are in $cm$ and $t$ is in $s$. The least distance between two successive crests in the wave is .... $m$. (in $.5$)

Which one of the following graphs represents the Freundlich adsorption isotherm?

Restriction enzymes were discovered by

The energy of an electron in the $3^{rd}$ orbit of a hydrogenic atom is $-E$. The energy of an electron in the first orbit will be

Photoelectric emission is observed from a metallic surface for frequencies $v_1$ and $v_2$ of the incident light rays $(v_1 > v_2)$. If the maximum values of kinetic energy of the photoelectrons emitted in the two cases are in the ratio of $1 : k$,then the threshold frequency of the metallic surface is