Electricity and magnetism (magnitude of current flowing)

[swankymotor16]

If the area of a tube is 0.0000283 m, with moving ions contributing to a magnetic field of 44.0x10^-4 T. What is the current flowing through the tube? [permeability of free space 'mu subzero'= 4∏x10^-4].

I don't have a clue of how to start attacking this problem, have a genius professor, but horrible professor.

 

[swankymotor16]

If the area of a tube is 0.0000283 m, with moving ions contributing to a magnetic field of 44.0x10^-4 T. What is the current flowing through the tube? [permeability of free space 'mu subzero'= 4∏x10^-4].

I don't have a clue of how to start attacking this problem, have a genius professor, but horrible professor.

radius is 3.0mm

 

[swankymotor16]

A 1000-turn toroidal solenoid has a central radius of 4.2 cm and is carrying a current of 1.7 A. What is the magnitude of the magnetic field inside the solenoid at the central radius? (μ0=4∏×10^-7 T ∙ m/A) r= 4.2cm= 0.042m

B=(μ0)(I)/(2∏)(r) ⇔ (4∏×10^-7)(1.7)/(2∏)(0.042) ⇔ 1.43x10^-8 T? Or does the 1000-turn toroidal affects in the magnetic field in some sort of a way?