7: A 2 mA current passes through a 1.4 cm long solenoid producing a magnetic field of .162 G. How many turns are in the solenoid

The number of turns is 64449395

Explanation:

The expression for the solenoid formula is stated below, and it is what we are going to use to solve for the number of turns

B= μ₀nl

where B= magnetic field

           μ₀= permeability , 4π × 10⁻⁷ Henry

           n= number of turns

            l= length of coil

Given data

current I=  2 mA

length L= 1.4 cm to meter we have 0.014

magnetic field B= 0.162 T

From the expression we can make n subject of formula we have

n=B/μ₀l

Substituting we have

n= 0.162/4π × 10⁻⁷*2*10^-3

n= 0.162/8π × 10^⁻10

n= 0.162/2.5136*10^-9          

n= 64449395

vapour or gas assuming atmospheriv pressure

i think the answer is a, hope this : )