The very top of the film shows no reflected light, indicating that the thickness is less than 1/4 the wavelength of visible light within the film, since the phase change on reflection for the beam from the first surface of the film is ï radians and the phase change on reflection from the second surface of the film is 0 radians, making the interfering rays mostly out of phase from that part of the film. given this information, what is the approximate thickness of the film at the first bright fringe counting from the top of the film, in terms of the wavelength of light in vacuum î», and the refractive index of the film n?

Consider a uniformly charged ring in the xy plane, centered at the origin. the ring has radius a and positive charge qdistributed evenly along its circumference. a)what is the direction of the electric field at any point on the z axis? . b)what is the magnitude of the electric field along the positive z axis? use k in your answer, where k=14πϵ0. d)the ball will oscillate along the z axis between z=d and z=−d in simple harmonic motion. what will be the angular frequency ω of these oscillations? use the approximation d≪a to simplify your calculation; that is, assume that d2+a2≈a2. express your answer in terms of given charges, dimensions, and constants