Calculate the current (in $mA$) required to deposit $0.195 \ g$ of platinum metal in $5.0 \ hours$ from a solution of $[PtCl_6]^{2-}$ : (atomic weight: $Pt = 195$)

The heat evolved for the rise of water when one end of the capillary tube of radius $r$ is immersed vertically into water is (Assume surface tension $= T$ and density of water to be $\rho$)

The magnetic field at the centre of a circular current-carrying conductor of radius $r$ is $B_c$. The magnetic field on its axis at a distance $r$ from the centre is $B_a$. The value of $B_c : B_a$ will be:

Two uniform strings $A$ and $B$ made of steel are made to vibrate under the same tension. If the first overtone of $A$ is equal to the second overtone of $B$ and if the radius of $A$ is twice that of $B,$ the ratio of the lengths of the strings is

Statement $S$: Presence of a rigid cell wall and nucleoprotein as genetic material.
Statement $R$: Examples include $Euglena$,$Dinoflagellates$,$Amoeba$,and $Paramecium$.

Two solid spheres $A$ and $B$ made of the same material have radii $r_A$ and $r_B$ respectively. Both the spheres are cooled from the same temperature under the conditions valid for Newton's law of cooling. The ratio of the rate of change of temperature of $A$ and $B$ is :