[amp_mcq option1=”100% of the previous value” option2=”50% of the previous value” option3=”series motor, if the armature current is reduced by 50%, the torque of the motor will be equal to A. 100% of the previous value B. 50% of the previous value C. 25% of the previous value” option4=”10% of the previous value” correct=”option3″]
The correct answer is: C. 25% of the previous value.
In a D.C. series motor, the torque is proportional to the square of the armature current. Therefore, if the armature current is reduced by 50%, the torque will be reduced by 75%, or 25% of the previous value.
Option A is incorrect because the torque will not be equal to 100% of the previous value. Option B is incorrect because the torque will not be equal to 50% of the previous value. Option D is incorrect because the torque will not be equal to 10% of the previous value.