Question

what is the mechanical power developed by a DC series motor is maximum
a) back emf is equal to half the applied voltage
b) back emf is equal to applied voltage
c) back emf is equal to zero
d) none of the above ​

Answer 1

Your answer is in above pic. I hope you got it. pls mark as brainliest

Answer 2

Answer:

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Explanation:

for motor,Eb :- Vt-laRa

mechanical power develop by the motor is given by

Pm:- EbIa :- VtIa - Ia^2 Ra

mechanical power develop develop by the motor will be miximum if dPm / dIa is zero

i.e, Vt -2IaRa :- 0 :- IaRa :- Vt/2

:. black emf Eb:- Vt -Vt/2:-Vt/2.

I HOPE IT HELP YOU