Answer:
the average kinetic energy of water particles - C.
Nope Copper is a better conductor
Answer:
Number of turns per unit length will be 
Explanation:
We have given that strength of the magnetic field produced by the solenoid B = 7 T
Current in the solenoid i = 200 A
Let the number of turns per unit length is n
Magnetic field due to solenoid is given as
here
is permeability of free space n is number of turns per unit length and i is current
So 

Answer: Descartes was more of speed which defers from modern day velocity.
Explanation:
Descartes law if conservation referred or defined “motion” rather than “momentum” as what is obtainable in today's world as ”speed” the rate at which something moves rather than “velocity” which is a product of speed and direction. So in conclusion Descartes was more of speed which defers from modern day velocity.