Use a current with a general current intensity of I in the long straight conductor, and place a metal bar ab with a length of L on the plane of the long straight conductor, which is perpendicular to t

Use a current with a general current intensity of I in the long straight conductor, and place a metal bar ab with a length of L on the plane of the long straight conductor, which is perpendicular to the conductor. 1, take an infinitely long straight line as the y axis, take infinitesimal elements, and specify the integration direction.

2. Use Faraday's law of electromagnetic induction to solve electromotive force.

Magnetic field B=uI/2πr generated by an infinite straight wire.

Magnetic flux =∫Bds=∫uI/2πr*a*dr, and the upper and lower integral limits are b to 2b.

Magnetic flux =uIaln2/2π.

U is the permeability in vacuum and I is the current.

Extended data:

Definite integral and indefinite integral seem to have nothing to do, but they are closely related in essence because of the support of an important theory in mathematics. It seems impossible to subdivide a graph infinitely and then accumulate it, but because of this theory, it can be transformed into calculating integral.

If f(x) is a continuous function on [a, b] and f'(x)= f(x), then

Expressed in words: the value of the definite integral formula is the difference between the value of the original function at the upper limit and the value of the original function at the lower limit.

It is precisely because of this theory that the relationship between integral and Riemann integral is revealed, which shows its important position in calculus and even higher mathematics. Therefore, Newton-Leibniz formula is also called the basic theorem of calculus.

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