The equation for light intensity in maximum, analogous to the equations of strong theory and Kirchhoff formula, is obtained on a basis of experimentally determined existence of deflection of light beams in the range of screen edge and regularity determining it and formation of diffraction fringes by a slit owing to interference of the beams propagating from the ranges near opposite edges of the slit.
deflection, light beams, deflection zone, area of screen's edge