Answer:
The value is 
Explanation:
From the question we are told that
The length of the solenoid is 
The magnetic field is 
The current is 
The desired temperature is 
Generally the magnetic field is mathematically represented as

=> 
Here
is the permeability of free space with value

So

=> 
It would be 20 protons left because 1-19= 20
Answer:
the answer to the question is a system of insulating element designed to control the path of electric current for a particular purpose
Complete question:
The exit nozzle in a jet engine receives air at 1200 K, 150 kPa with negligible kinetic energy. The exit pressure is 80 kPa, and the process is reversible and adiabatic. Use constant specific heat at 300 K to find the exit velocity.
Answer:
The exit velocity is 629.41 m/s
Explanation:
Given;
initial temperature, T₁ = 1200K
initial pressure, P₁ = 150 kPa
final pressure, P₂ = 80 kPa
specific heat at 300 K, Cp = 1004 J/kgK
k = 1.4
Calculate final temperature;

k = 1.4

Work done is given as;

inlet velocity is negligible;

Therefore, the exit velocity is 629.41 m/s