question_answer

A horizontal straight wire 20 m long extanding from to east to west falling with a speed of 5.0 M\s, at right angles to the horizontal component of the earth's magnetic field \[0.30\times {{10}^{-4}}Wb/{{m}^{2}}.\]The instantaneous Value of the e.m. f. induced in the wire will be :                                    [AIEEE 11-05-2011]

A) 3 mV

B) 4.5 mV

C) 1.5 mV

D) 6.0m V

Correct Answer: A

Solution :

[a]

\[{{\varepsilon }_{Ind}}=Bv\ell \]

\[=0.3\times {{10}^{-4}}\times 5\times 20\]

\[=3\times {{10}^{-3}}v\]

\[=3mv.\]