Answer:
Option B is correct.
Explanation:
We define our equation for Inductance, that is,
[tex]L = \frac{\mu_0 N^2 *A}{l}[/tex]
Where [tex]\mu_0[/tex] is the permeability of the core material
A= is the cross-sectional Area
N is the number of turns
l= is the lenght of the coil in meters
But we need also a expression for the Energy Stored, that equation is given by,
[tex]U = \frac{1}{2} LI^2[/tex]
Where,
L is the inductance and I is the current.
We know that U always is going to be proportional to the number of turns and the current.
Therefore we can conclude that the proportion
[tex]\frac{N_2}{N_1} = \frac{I_1}{I_2}[/tex]
Always remains same.
In this way the expresion
[tex]\frac{1}{2} = \frac{I_1}{I_2} \Rightarrow I_2 = 2*I_1[/tex]
Then it mus be two times larger
