Question

If the speed of rotation for a four pole, 220V dc machine is 1 m/s, flux density as 2T having length of bore as 0.1m and radius of 0.5m. The emf induced under pole faces will be ________

(a) 0.2 V

(b) 0.1 V

(c) 0.2*pi V

(d) 220 V

I got this question by my school principal while I was bunking the class.

My doubt is from EMF Generated in the Armature in portion Electromechanical Energy Conversions of Electrical Machines

Answer 1

Right answer is (a) 0.2 V

To elaborate: E = B*l*v

               = 2*0.1*1

        = 0.2 Volts.