Question

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

Answer 1

Answer:

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,

$B=\mu_0 nI$

Here, $\mu_0$ is the absolute permittivity

$n$ is the number of turns

$I$ 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

Answer 2

Answer:

The correct answer is;

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

Explanation:

For a solenoid which consists of a cylinder wrapped with a thin wire round the cylinder we have that there is negligible magnetic field produced outside of the solenoid when current passes through the wire. There is however a uniform field inside, parallel to the axis of the cylinder, given by

B = U×n×I

Where

U = Permeability of free space

I = Current

n = Number of turns per unit length

Therefore overwrapping the entire solenoid with a current carrying conductor will increase the strength of the magnetic field inside the solenoid.