Yah isnt that obvious? Gasses mix everywhere in all proportions.
Have a universal record base. Everyone is able to understand the data compiled since the same measurement systems are being used around the world. This is just to simplify all of the information.
Because of Surface tension
Answer:
B, It reacts with oxygen to form a new substance
Explanation:
B
Answer:
The induced emf between two end is
V
Explanation:
Given:
Length of rod
m
Height
m
Magnetic field
T
For finding induced emf,

Where
velocity of rod,
For finding the velocity of rod.
From kinematics equation,

Where
initial velocity, 



Put the velocity in above equation,

V
Therefore, the induced emf between two end is
V