A conducting bar moves on two conducting rails as shown in the figure. A constant magnetic field B exists into the page. The bar starts to move from…

A conducting bar moves on two conducting rails as shown in the figure. A constant magnetic field B exists into the page. The bar starts to move from the vertex at time $\displaystyle \mathrm{t}=0$ with a constant velocity. If the induced EMF is $\displaystyle \mathrm{E} \propto \mathrm{t}^{\mathrm{n}}$, then value of n is $\displaystyle \_\_\_\_$.