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 

Combustion Engine Exhaust----Cars, trucks, jet airplanes and other combustion engine vehicles cause air pollution. The exhaust from these contains carbon monoxide, nitrous oxide and gaseous oxide. This type of air pollution creates smog
Answer:
Material's density
Explanation:
Seismic waves travel at different rates of speed based on a material's density. Hopefully, you understand that the Earth has three main layers: the crust, mantle, and core. Earthquake waves move faster through solids.
Wavelength = (speed) / (frequency)
= (3 x 10⁸ m/s) / (1 x 10⁸ /s) = 3 meters
Answer:
360 ÷ 4 = 90
Example
A 360° circle is cut into 4 peaces in the form of + or × . It's one side is called 90°