When two pulses with different amplitudes intersect at a point 'P' in a string, they superpose and form a resultant pulse. The superposition principle states that when two waves meet, the resulting displacement at any point is the algebraic sum of the individual displacements caused by each wave.
At the point of intersection 'P', the individual pulses combine to form a resultant pulse due to their superposition. This resultant pulse will have an amplitude that is the algebraic sum of the amplitudes of the individual pulses at that point. The specific characteristics of the resultant pulse, such as its amplitude, shape, and velocity, will depend on the relative amplitudes, phases, and wavelengths of the original pulses.
However, after the intersection at 'P', each individual pulse continues to travel undisturbed with its original velocity and amplitude. This is because the superposition of waves does not alter the original waves themselves; it only affects the resulting displacement at each point where the waves overlap.
As the pulses move away from the point of intersection, they propagate independently without influencing each other. The individual pulses maintain their original properties, including their amplitudes and velocities, and continue to travel through the medium undisturbed. The reason for this is that waves on a string, for example, do not interact directly with each other once they have passed each other, and they continue along their respective paths independently.