SSC JE Electrical Engineering 2017 Set 4 Paper

A simple method of increasing the voltage of a DC generator is to increase the speed of rotation.
Back EMF of DC generator is proportional to speed EMF $\propto \mathrm{\varphi }\mathrm{\omega }.$
If speed is increase the Emf of a generator increase
$\uparrow \mathit{V}=\mathit{E}\uparrow {\mathit{I}}_{\mathit{a}}{\mathit{R}}_{\mathit{a}}$
emf is increase then terminal voltage is increase