Answer:

Explanation:
Given that,
The speed of an electromagnetic wave traveling in a transparent nonmagnetic substance is given by :

Where
k is the dielectric constant of the substance.
v is the speed of light in water


So, the speed of light in water is 
Answer:
it is light
Explanation:
the arrow that says light is on the glass it must be near from tungsten
Explanation:
It is given that,
An electron is released from rest in a weak electric field of, 
Vertical distance covered, 
We need to find the speed of the electron. Let its speed is v. Using third equation of motion as :

.............(1)
Electric force is
and force of gravity is
. As both forces are acting in downward direction. So, total force is:



Acceleration of the electron, 


Put the value of a in equation (1) as :


v = 0.010 m/s
So, the speed of the electron is 0.010 m/s. Hence, this is the required solution.