72.
The absorption of ink by blotting paper involves

73.
Water from soil enters into the root hairs owing to :

74.
Which of the following liquids has the least density ?

75.
A small drop of oil spreads over water because :

76.
Two rods, one of copper and other of steel, experience the same upthrust when placed in water.Thus, both have

77.
If ice floating on water in a vessel melts, the water level in the vessel ________ .

78.
On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because

79.
The velocity of falling rain drops attains a terminal value because of

80.
Which one is the unit of surface tension of a liquid