Answer:14.2 mV
Explanation:
Given
Length of steel beam [tex]L=17\ m[/tex]
Magnetic field [tex]B=30\ \muT[/tex]
speed of beam [tex]v=28\ m/s[/tex]
Now consider as beam slides it encloses an area of rectangle of
width [tex]w=17\ m and length L'=v\times t [/tex]
Area [tex]A=17v\cdot t[/tex]
and Induced EMF is [tex]V=-\frac{d(BA)}{dt}[/tex]
[tex]V=-B\frac{d(17vt)}{dt}[/tex]
[tex]V=-17Bv[/tex]
[tex]V=-17\times 30\times 10^{-6}\times 28[/tex]
[tex]V=-14.2\ mV[/tex]
Magnitude of EMF[tex]=14.2\ mV[/tex]