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A D.C. motor working on 200V have initia...

A D.C. motor working on 200V have initial current of 5A but when it attained maximum velocity, the current obtained is 3A. What will be its Back emf ?

A

0V

B

80 V

C

120 V

D

200 V

Text Solution

Verified by Experts

The correct Answer is:
B
`R=E/I=200/5=40 Omega`
Now `I=(E-epsilon)/R rArr 3= (200-epsilon)/40`
`therefore120=200-epsilon`
`therefore epsilon` =80 V
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