Lenz's law of electromagnetic induction corresponds to the

A square of side $L$ lies in the $x-y$ plane，where the magnetic field is given by $B=B_0(2 \hat{i}+3 \hat{j}+4 \hat{k})$ where $B_0$ is constant．The magnetic flux passing through the square is $L$

A uniform but time varying magnetic field is present in a circular region of radius ' $R$ '. The magnetic field is perpendicular and into the plane of loop and the magnitude of field is increasing at a constant rate $\alpha$. There is a straight conducting rod of length 2 R placed as shown in figure. The magnitude of induced emf across the rod is

Two straight conducting plates form an angle $$\theta$$ where their ends are joined. A conducting bar in contact with the plates and forming an isosceles triangle with them starts at the vertex at time $$t=0$$ and moves with constant velocity $$\vec{v}$$ to the right as shown in figure. A magnetic field $$\vec{B}$$ points out of the page. The magnitude of emf induced at $$t=1$$ second will be