Electricity Physics

Question

 A solenoid is 0.40 m long with a cross sectional area of 0.0008 m2 and wound with 300 turns of wire.  If a current of 1.2 A is running through the solenoid, what is the magnetic field in the solenoid' score and what is the flux through the solenoid?

Answer 1

 Hi Doug 

 

I have assumed the solenoid to be long (as area is small compared to length)

Magnetic Field in side a long solenoid is given as 

 

B = µ₀ n I  ( in Tesla)

Where µ₀  is permeability of free space

n = Number of turns per unit length

I = Current in solenoid

 

µ_{0 = 4 pi x 10^{- 7} Si Units}

So magnetic field = B = 11.304 x 10 ^-4 Tesla or 1.130 x 10 ^-3 Tesla or Weber /m²

Magnetic flux inside a solenoid = Bx Area = 1.13x 10^-3 x0.0008 Weber = 9.04 x 10 -7 Weber