The relative humidity on a day,when the partial pressure of water vapour is $0.012 \times 10^5 \, Pa$ at $12^{\circ}C$,is ......... $\%$. (Take the vapour pressure of water at this temperature as $0.016 \times 10^5 \, Pa$.)

Consider the following statements:
$A.$ Surface tension arises due to extra energy of the molecules at the surface as compared to the molecules in the interior of a liquid.
$B.$ As the temperature of a liquid rises, the coefficient of viscosity increases.
$C.$ As the temperature of a gas increases, the coefficient of viscosity increases.
$D.$ The onset of turbulence is determined by Reynolds number.
$E.$ In a steady flow, two streamlines never intersect.
Choose the correct answer from the options given below:

In a water voltameter,the electrolysis of ...... takes place.

The diagram shows a cup of tea seen from above. The tea has been stirred and is now rotating without turbulence. $A$ graph showing the speed $v$ with which the liquid is crossing points at a distance $X$ from $O$ along a radius $XO$ would look like:

Why is skating possible on ice?

Given below are two statements:
Statement $I$: Pressure of fluid is exerted only on a solid surface in contact as the fluid-pressure does not exist everywhere in a still fluid.
Statement $II$: Excess potential energy of the molecules on the surface of a liquid,when compared to interior,results in surface tension.
In the light of the above statements,choose the correct answer from the options given below.