A rectangular loop of length \(\ell=4 \mathrm{~cm}\), width \(w=3 \mathrm{~cm}\), and internal resistance \(R=0.5 \mathrm{~V} / \mathrm{A}\) is located so that the normal to the loop is parallel to a uniform magnetic field. Suddenly, the loop is turned upside down. A galvanometer measures the total amount of charge flowing through the loop in this time interval to be \(1.5 \mathrm{mC}\). What is the magnitude of the magnetic field?