Answer:
The current must be 5 times larger
Explanation:
The equation for Inductance, is given by;
L = (μ_o•N²•A)/l
Where;
μ_o is the permeability of the core material
N is the number of turns
A is the cross sectional Area
l is the length of the coil in meters
L is the inductance
However, we also need to find an expression for the Energy Stored, and the equation is given by;
U = (1/2)LI²
Where;
L is the inductance
I is the current.
We also know that U is proportional to the number of turns and the current.
Thus, we can conclude that;
N_2/N_1 = I_1/I_2
From the question, we are told that the number of turns is reduces by 1/5. Thus,
1/5 = I_1/I_2
So, I_2 = 5I_1
So the current must be 5 times larger
