Consider a solenoid that is very long compared with its radius. Of the following choices, what is the most effective way to increase the magnetic field in the interior of the solenoid? (Hint: Page 783, equation 29.17) A. Double its length, keeping the number of turns per unit length constant B. Reduce its radius by half, keeping the number of turns per unit length constant C. Overwrap the entire solenoid with an additional layer of current-carrying wire

C. Overwrap the entire solenoid with an additional layer of current-carrying wire

Explanation:

The most effective way to increase the magnetic field in the interior of the solenoid is

Formular to calculate magnetic field in the interior is,

Here, is the absolute permittivity

is the number of turns

is the current flowing in the wire.

From the above formular, the magnetic field depends upon the current flowing and the number of turns over the solenoid

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it