A 110 V DC machine has an armature resistance of 2 ohm. If the full load current is 15 A, the difference in induced voltage when the machine is running as a motor, and as a generator is:

Correct option is C

$$\bullet \ \text{The difference in induced voltage when the machine is running as a motor, and as a generator is} \\[6pt]= \ E_g - E_m \\[6pt]= \ v + i_a R_a - (v - i_a R_a) \\[6pt]= \ 2 i_a R_a \\[10pt]\text{Given} \\\Rightarrow \ I = 15~\text{A} \\\Rightarrow \ R = 2~\Omega \\[6pt]\text{On putting values in} \\[4pt]\Rightarrow \ 2 i_a R_a \\[4pt]\Rightarrow \ 2 \times 15 \times 2 = 60~\text{V}$$​​