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The problem of diffraction of electromagnetic waves by a black screen, as defined by Kottler, is reconsidered. The solution proposed by Kottler does not satisfy one of the conditions of the problem; hence it is incorrect.

The problem of diffraction of electromagnetic waves by a black screen, as defined by Kottler, is reconsidered. The solution proposed by Kottler does not satisfy one of the conditions of the problem; hence it is incorrect.

The problem of scattering of a scalar plane wave by a prolate spheroid is solved for Neumann boundary condition, arbitrary major to minor axis ratio, and arbitrary incident direction. The solution is obtained by using an iterative method applied to solutions of the corresponding potential problem and is expressed as a series of products of Legendre and trigonometric functions and ascending powers of wave number. A recursion relation for the coefficients in this series is derived. These results and the corresponding results for the Dirichlet case are employed to calculate scattering cross-sections for 2: 1, 5: 1 and 10: 1 prolate spheroids.

The problem of scattering of a scalar plane wave by a prolate spheroid of revolution is solved for Dirichlet boundary condition, arbitrary major to minor axis ratio, and arbitrary incident direction. The solution is obtained by using an iterative method applied to solutions of the corresponding potential problem and is expressed as a series of products of Legendre and trigonometric functions, and ascending powers of wave number. A recursion relation for the coefficients in this series is derived.

The complete low frequency expansion of the field scattered when a plane wave is incident upon an oblate spheroid or a disk is obtained for either Dirichlet or Neumann boundary conditions.