A soft ferromagnetic material is placed in an external magnetic field. The magnetic domains :

Which of the following equations represents a travelling wave?

Two electrons each are fixed at a distance '2d'. A third charge proton placed at the midpoint is displaced slightly by a distance x (x << d) perpendicular to the line joining the two fixed charges. Proton will execute simple harmonic motion having angular frequency : (m = mass of charged particle)

On the basis of kinetic theory of gases, the gas exerts pressure because its molecules :