Given below are two statements :

Statement I : Electromagnetic waves are not deflected by electric and magnetic field.

Statement II : The amplitude of electric field and the magnetic field in electromagnetic waves are related to each other as $${E_0} = \sqrt {{{{\mu _0}} \over {{\varepsilon _0}}}} {B_0}$$.

In the light of the above statements, choose the correct answer from the options given below :

The time taken by an object to slide down 45$$^\circ$$ rough inclined plane is n times as it takes to slide down a perfectly smooth 45$$^\circ$$ incline plane. The coefficient of kinetic friction between the object and the incline plane is :

For the given figures, choose the correct options :

An object moves at a constant speed along a circular path in a horizontal plane with center at the origin. When the object is at $$x=+2~\mathrm{m}$$, its velocity is $$\mathrm{ - 4\widehat j}$$ m/s. The object's velocity (v) and acceleration (a) at $$x=-2~\mathrm{m}$$ will be