A conducting square loop of side $L$ and resistance $R$ moves in its plane with a uniform velocity $v$ perpendicular to one of its sides. A magnetic induction $B$ constant in time and space, pointing perpendicular and into the plane at the loop exists everywhere with half the loop outside the field. The induced emf is\\
(1) zero\\
(2) $RvB$\\
(3) $VBL/R$\\
(4) $VBL$