Find the average induced voltage in a coil of an area 500 cm2 and having 1000 turns, when it is turned through 1800 in 0. 1 s. It is also given that the coil is initially placed perpendicularly to a uniform field of 0.4 gauss.

Here, A=500cm2=500×10−4m2N=1000,B=0.4G=0.4×10−4Tt=110sWhen the coil is held perpendicular to the filed, the normal to the plane of the coil makes an angle of 00  with the field B.∴ Initial flux, ϕ1=BAcos0∘=BA final flux,  ϕ2=BAcos180∘=−BAAverage induced emf, ε=−Nϕ2−ϕ1t=−N−BA−BAt=2NBAt=2×1000×0.4×10−4×500×10−41/10= 0.04 V