A uniform magnetic field exists in the region given by B→=3i^+4j^+5k^ .  A rod of length 5 m placed along Y-axis is moved along X-axis with constant speed 1 ms−1 .  Then induced e.m.f in the rod is

l=5jV=1ie=Bl×V=Bi^j^k^050100=B0−5K^3i^+4j^+5k^.−5k^=25VConceptual approach:-As the rod is placed along Y axis and moving in x direction, the magnetic field has to be perpendicular to both l→andv→ in order to develop motional emf. Hence the z component of the magnetic field should be taken.