A 240v dc shunt motor with an armature resistance of 0.5  has a full load current of 40A

Q. A 240v dc shunt motor with an armature resistance of 0.5  has a full load current of 40A. Find out the ratio of the stalling torque to the full load torque when a resistance of 1 ohm is connected in series with the armature

A.            12

B.            6

C.            4

D.            10

Answer: 4