When sound enters water from air or vice-versa, which physical quantity of the waves remains unchanged?

when sound enters from air or vice - versa, which physical quentity of the waves ramains unchanged ?

What quantity remains unchanged in FM wave?

What quantity remains unchanged in AM wave?

When light enters from glass to water, which of the following quantity remains unchanged ?

When a copper sphere is heated, which physical quantity of the sphere will show maximum percentage change?

When light moves from glass to air, the property of it which remains unchanged is

Which quantity remains unchanged in case of a projectile ?

A particle is acted upon by a constant power. Then, which of the following physical quantity remains constant?

When light is refracted from a surface, which of its following physical parameters does not change?