Which of the following functions of $A$ and $B$ may be performed if $A$ and $B$ possess different dimensions

- A
$\frac{A}{B}$

- B
$A + B$

- C
$A -B$

- D
none

If the terminal speed of a sphere of gold (density $= 19.5\, kg/m^3$ ) is $0.2\, m/s$ in a viscous liquid (density $= 1.5\, kg/m^3$ ), find the terminal speed of a sphere of silver (density $=10.5\, kg/m^3$ ) of the same size in the same liquid ........ $m/s$

Water rises to a height of $10\, cm$ in capillary tube and mercury falls to a depth of $3.1\,cm$ in the same capillary tube. If the density of mercury is $13.6$ and the angle of contact for mercury is $135^o$, the approximate ratio of surface tensions of water and mercury is

What is the pressure on a swimmer $20 \,m$ below the surface of water is ..... $atm$

A manometer reads the pressure of a gas in an enclosure as shown in the figure.

The absolute and gauge pressure of the gas in $cm$ of mercury is

(Take atmospheric pressure $= 76\,cm$ of mercury)

A soap bubble in vacuum has a radius $3\, cm$ and another soap bubble in vacuum has radius $4\, cm$. If two bubbles coalesce under isothermal condition. Then the radius of the new bubble will be .............. $\mathrm{cm}$