7) A wire, 100 mm long, is moved at a uniform speed of 4 m/s at right angles to its length and to a uniform magnetic field. a) Calculate the density of the field if the e.m.f. generated in the wire is...

7) A wire, 100 mm long, is moved at a uniform speed of 4 m/s at right angles to its length and to a uniform magnetic field. a) Calculate the density of the field if the e.m.f. generated in the wire is 0.15 V. b) If the wire forms part of a closed circuit having a total resistance of 0.04 Ω, calculate the force on the wire in newtons.