can you please assist with this questions Q3 and Q4

Question 3. Magnetism 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. Calculate a) the density of the field if the e.m.f. generated in the wire is 0.15 V. (4 ) b) If the wire forms part of a closed circuit having a total resistance of 0.04 Q. Calculate the force on the wire in newtons (3) [7] Question 4. Magnetic Circuits A coil of 450 turns is wound uniformly round a cast steel ring. The ring has a cross-sectional area of 750mm? and a mean circumference of 600mm. A flux of 0.825mWb is produced in the ring. (Given that H = 800At/m at that flux). 4.1 Calculate the reluctance of the ring. (6) 4.2 Calculate the current required to produce the given flux (4) [10]