A 300 V D.C. shunt motor runs at 300 r.p.m. ,takes 10 A and induces the emf of 50V. The armature and field resistance is 20 ohms and 200 ohms respectively. The 200 ohm is added to field circuit...

A 300 V D.C. shunt motor runs at 300 r.p.m. ,takes 10 A and induces the emf of 50V. The armature and field resistance is 20 ohms and 200 ohms respectively. The 200 ohm is added to field circuit increase speed to 900 r.p.m. . Assume flux proportional to field current. Then induced emf during 900rpm is (estimated time 2 minutes)

a.
75 V

b.
300 V

c.
200 V

d.
100 V