Light waves falling into a black hole We know that as light falls into a black hole it is stretched due to unequal tidal forces acting on it and hence it looses energy . Then is it possible that as the light gets stretched each succeeding term of wavelength forms a progression? Like an A.P , G.P or H.P?
 A: I don't think that light would be stretched, more exactly there is currently no theory what could describe quantummechanical phenomena in strongly curved spacetime. But a lot of people are working hardly on that.
Even if there would be such a theory, this "tidal stretch of the photons" wouldn't happen around the event horizon, but nearing the singularity inside it. On the EH, the curvetime of the spacetime ($\approx$ tidal stretch) is not unavoidably high, and it shrinks with the mass of the BH. The high curvature is around the singularity.
The cause of the wavelength growth nearing the event horizon is not some "tidal force", but the gravitational time dilation.
A: We know that as light falls into a black hole it is "compressed" due to unequal coordinate velocities of its different parts. 
As light falls, its coordinate velocity decreases. The upper end of a light pulse is closing on the lower end of the light pulse, because the lower end has fallen more and has lower coordinate velocity.
