91Ó°ÊÓ

The principle of superposition states:

When two or more waves overlap, the resultant intensity at any point and at any instant is found by adding the intensity that would be produced at the point by the individual waves if each were present alone.

Since, the position of antipodal and nodal lines depends upon the wavelength, not on the amplitude. Thus, the positions of antipodal and nodal lines will remain the same.

The intensity $l$is proportional to the square of the amplitudes i.e., $I∞A^2$. When light from the two given sources interferes, there will be redistribution of the intensity of light, but at the points of anti-nodal curves, the resultant intensity will be less than what it would have been if the sources had equal amplitudes. Similarly, at points of nodal curves, the intensity will be small but not zero.

Hence, there is no change in the positions of the antipodal lines and nodal lines. There is a reduction in the reinforcement at points on the anti-nodal curves. Also, the total cancellation will not take place at points on the nodal curves.