Electromagnetism PYQ

A charged particle enters a uniform magnetic field perpendicular to its velocity. The path of the particle is:

A circular loop of radius R carries current I. The magnetic field at a point on the axis at distance x from the center is:

What is the direction of the magnetic field of the wave?

Find the wavelength of the wave in nanometres.

The magnetic flux through a coil changes from 5 Wb to 2 Wb in 0.1 s. The induced EMF is