Question

A wheel with 10 metallic spokes each 0.5 m long is rotated with a speed of 120 rev/min in a plane normal to the earth's magnetic field at the place.If the magnetic of the field is 0.4G, what is the induced emf between the axle and the rim of the wheel ?

Answer 1

we have no of spoken (N)=10 length of each spoke(L)=0.5m magnetic field (B)$=0.4\times {10}^{-4}$

$T=4\times {10}^{-5}$

frequency (f)$=120rpm=2rps$

induced emf between exle & rim is

given by,

$e=N\times B\times l^2\times \pi \times t$

$=10\times 4{\times }^{-5}\times 0.5\times 0.5\times 3.14\times 2v$

$=6.28\times {10}^{-5}V$