A Conducting Rod of Length $\ell = 25 \mathrm {~cm}$ Is Placed on A

A conducting rod of length $\ell = 25 \mathrm {~cm}$ is placed on a $U$ -shaped metal wire that is connected to a lightbulb having a resistance of $8.0 \Omega$ , as shown in the figure. The wire and the rod are in the plane of the page. A constant uniform magnetic field of strength $0.40 \mathrm {~T}$ is applied perpendicular to and into the paper. An applied external force pulls the rod to the right with a constant speed of $6.0 \mathrm {~m} / \mathrm { s }$ . What is the magnitude of the emf induced in the rod?

A) $0.40 \mathrm {~V}$
B) $0.20 \mathrm {~V}$
C) $0.50 \mathrm {~V}$
D) $0.60 \mathrm {~V}$
E) $0.30 \mathrm {~V}$