Consider a coil lying in the plane of the screen and the external magnetic field pointing into the screen. As the external magnetic field decreases, an induced current flows in the coil.
What is the direction of the induced magnetic field caused by this current?

The direction of the induced magnetic field should be pointing towards the screen.

Explanation:

Because the magnetic field is decreasing, and if we use Len's law, the induced current will increase the external magnetic field. For this increase to occur, said magnetic field produced by the induced current must be pointing towards the screen.

two charges are fixed in place on the x-axis as shown. the charge at x = 0 is negative and has magnitude q = 2 μcoulombs (1 μcoulomb = 10-6 coulombs). the charge at x = d, (d = +12 cm), is positive and has magnitude q = 4 μcoulombs. find a point x = xo along the x-axis at which the electric field is zero.