Refer Fig. 30. The e.m.f induced *(e) *in the conductor is given by:

*e *= *Blv *volt … (22)

where *B *= flux density of the magnetic field in *tesla, *

*l *= length of the conductor in *metres, *and

*v *= velocity of the conductor in *m/s. *

If the conductor moves at an angle e with the direction of flux then the induced e.m.f.

*e *= *Blv *sin

**Example ****26***. A *1.2 m *long conductor moves at right angles to a uniform magnetic field of flux density *1.8 *Wb */ m^{2} *with a velocity of 60 metres */ *second. Calculate the e.m.f. induced in it. *

*Find also the value of induced e.m.f. when the conductor moves at an angle of **30° **to the direction of the field. *

**Solution**. *Given: l *= 1.2 m ;

*B *= 1.8 *Wb/m ^{2} *;

*v *= 60 m/s

*(i) *Induced e.m.f., e = *Blv … *[See Fig. 33 (a)]

= 1.8 × 1.2 × 60 = **129.6 V. (Ans.)**

*(ii) *Induced e.m.f., e = *Blv *sin θ … [See Fig. 33 (b)]

= 1.8 × 1.2 × 60 × sin 30° = **64.8 V. (Ans.)**

**Example 27**. *In a four-pole dynamo, the flux/pole is *18 m *Wb. If the armature is driven at 600 r.p.m., what is the average e.m.f. induced in one of the armature conductors? *

**Solution**; Flux/pole = 18 m Wb;

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