The SI unit of plane angle is the radian; degree is a non-SI unit and steradian is the unit of solid angle.
184
If the terminal speed of a sphere of gold (density = 19.5 kg/m3) is 0.2 m/s in a viscous liquid (density = 1.5 kg/m3), find the terminal speed of a sphere of silver (density = 10.5 kg/m3) of the same size in the same liquid.
An arc equal to the radius subtends an angle of one radian at the center, so option C is correct.
186
Two spherical soap bubbles coalesce. If V is the consequent change in volume of the contained air and S is the change in the total surface area, if T is the surface tension of the soap solution, then (if p is atmospheric pressure)
Mass is an intrinsic property of matter and does not change with location, so it remains constant throughout the universe.
188
11. Density of mercury = 13.6 g cm^-3, density of a liquid = 1.36 g cm^-3. If the height of the mercury barometer is 76 cm, then the height of the liquid barometer is
Barometer height is inversely proportional to density: h_liquid = 76 × (13.6 / 1.36) = 76 × 10 = 760 cm.
189
Two bodies with volumes V and 2V are equalized on a balance. The larger body is then immersed in oil of density 0.9 gm/cc in which the smaller body is simultaneously immersed so as not to disturb the equilibrium. What must be the density of the liquid in which the smaller body is immersed?
