Answer:She can increase the number of wire loops
Explanation: When the number of loops of wire ( usually around the iron ) increases, the strength of the electromagnet is increased.
According to the equation
B=μ₀ N I
Where
μ₀ = permeability of the core
N= Number of turns of the coil
I= Current flowing through the coil
From the equation above , we can see that The strength of an electromagnet depends the amount of current, no of turns of coil and the permeability core of coil. we can now say that Increasing the number of wire loops increases the strength of electromagnet.
Therefore, Lisa should increase the number of wire loops to increase the strength of the electromagnet
