Line Current of A 500 V DC shunt motor is 52 A. shunt field and armature resistance are 250 Ω and 0.5 Ω respectively. Determine the back e.m.f.

Correct option is A

Given

​$$\begin{aligned}I_L &= 52 \text{ A} \\V &= 500 \text{ V} \\R_a &= 0.5 \Omega \\I_{sh} &= \frac{V_L}{R_f} \\&= \frac{500}{250} \\&= 2 \text{ A} \\I_a &= I_L - I_{sh} \\&= 50 \text{ A} \\E_b &= V_L - I_a R_a \\&= 500 - (50 \times 0.5) \\E_b &= 475 \text{ V}\end{aligned}$$​​