Question

# Figure a shows a circuit consisting of an ideal battery with emf $$\mathscr{E}=6.00\muV$$, a resistance R, and a small wire loop of area . For the time interval t = 10 s to t = 20 s, an external magnetic field is set up throughout the loop.The field is uniform, its direction is into the page in Figure a, and the field magnitude is given by , where B is in teslas, a is a constant, and t is in seconds. Figure b gives the current in the circuit before, during, and after the external field is set up. The vertical axis scale is set by . Find the constant a in the equation for the field magnitude.

Medium
Updated on : 2022-09-05
Solution
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## From the datum at in Fig. b we see which implies that the resistance isNow, the value of the current during leads us to equateThis shows that the induced emf is . Now we use Faraday's law:Plugging in and we obtain

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