please answer :

Question

A solenoid is 3.0 cm long and has a radius of 0.50 cm. It is wrapped with 500 turns of wire

carrying a current of 2.0 A. The magnetic field at the center of the solenoid is:

Answer 1

Dorsa,

The equation you need to solve this is (magnetic field) = (permeability)*(number of turns)*(current)/(length) which as symbols is written: B = μNI/L.You have provided all the information needed except for one thing - the value you use for "permeability" depends on what the core/center of the solenoid is made of. It's most likely either iron/steel or air. Regardless of the material, what you need to do to find the permeability is use this equation: μ=kμ₀ where μ₀ is a constant (called "vacuum permeability) equal to 1.26×10⁻⁶ H/m and k is called "relative permeability" and you can look up the value for your material. If it's air then k=1, for a metal k will be much larger than 1, but the exact number depends on the type of metal.

Simon