Two objects A and B are separated horizontally by distance ' a '. Object B moves in a direction perpendicular to distance ' $a$ ' with velocity ' $V_1$ '. Simultaneously object A covers shortest distance with velocity ' $V$ ' and meets object $B$ in time ' $t$ '. The time ' $t$ ' is given by
Pressure of the gas remaining same, the temperature at which r. m. s. speed of the gas molecules is double its value at $27^{\circ} \mathrm{C}$ is
In a single slit diffraction experiment, slit of width ' a ' and incident light of wavelength $5600 $$\mathop {\rm{A}}\limits^{\rm{o}} $, the first minimum is observed at angle $30^{\circ}$. The first secondary maximum is observed at angle $\left(\operatorname{Sin} 30^{\circ}=0.5\right)$
If $R_1$ and $R_2$ are the radii of the atomic nuclei of mass numbers 27 and 125 respectively, then the ratio $R_2: R_1$ is