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- Homework Statement
- - The pick up (magnet with coil wound around) of an electric guitar is such that in coil, formed by 10 circular turns with a radius of 4 cm and whose surfaces are perpendicular to the lines of force of the magnetic field, an induced current of 2 x 10^(-4) A arises when the field average magnetic on the surface of the coil passes from an unknown value B1 to a value of 2.3 T in 0.05 s. Determine the initial magnetic field knowing that the coil has a resistance of 2000 Ω and neglecting Lenz's law.

- Consider an area of 3.96m^2; it is immersed in a uniform magnetic field B0 = 0.9 T crossed perpendicularly by the lines of B. At a certain instant the intensity of the field begins to vary over time according to the law:

𝐵 (𝑡) = 𝐵0 (0.4𝑡^2 - 𝑙𝑛𝑡). To determine:

▪ the instant in which the electromotive force is zero.

▪ The absolute value of the electromotive force induced in the loop at the instant t = 5 s and of the induced current knowing that the loop resistance is 10 Ω.

- Relevant Equations
- Faraday's Law

Hi, I was practicing some problems on the magnetic field and the electromotive force, when I got stuck on these two exercises. Could you help me figure out how to proceed?

In the first problem, I tried to find the magnetic field flux by multiplying the induced current for ∆t and R. Should I now divide this result by the number N of turns?

In the second exercise, I started setting the flux equal to 0, then I'm at an impasse

In the first problem, I tried to find the magnetic field flux by multiplying the induced current for ∆t and R. Should I now divide this result by the number N of turns?

In the second exercise, I started setting the flux equal to 0, then I'm at an impasse