A conducting rod moves perpendicularly through a uniform magnetic field. How does the emf change if the magnetic field is increased by a fac

Question

A conducting rod moves perpendicularly through a uniform magnetic field. How does the emf change if the magnetic field is increased by a factor of 4 and the time required for the rod to move through the field is decreased to half of the original time?
a) It increases by a factor of 2
b) It increases by a factor of 4
c) It increases by a factor of 8
d) It increases by a factor of 16 .

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Kim Cúc 1 week 2021-07-21T20:54:51+00:00 1 Answers 2 views 0

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    2021-07-21T20:55:52+00:00

    Answer:

    c) It increases by a factor of 8

    Explanation:

    According to Faraday’s law (and Lenz’ law), the induced EMF is given as the rate of change of magnetic flux.

    Mathematically:

    V = -dФ/dt

    Magnetic flux, Ф, is given as:

    Ф = BA

    where B  = magnetic field strength and A = Area of object

    Hence, induced EMF becomes:

    V = -d(BA)/dt  or -BA/t

    If the magnetic field is increased by a factor of 4, (B_n = 4B) and the time required for the rod to move is decreased by a factor of 2 (t_n = t/2), the induced EMF becomes:

    V_n = -(B_nA)/t_n

    V_n = \frac{-4BA}{(t/2)}\\\\V_n = \frac{-8BA}{t} \\\\V_n = 8V\\

    The EMF has increased by a factor of 8.

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )