A very thin oil film (noil=1.25) floats on water (nwater=1.33). What is the thinnest film that produces a strong reflection for green light with a wavelength of 500 nm? Which of the following equations should be used to find the minimum thickness t of the oil film that satisfies the conditions of the problem? Let λ be the wavelength of light in air and n the index of refraction of the thin filma. 2t=mλn(m=0,1,2,...) for constructive interference. b. 2t=(m+12)λn(m=0,1,2,...) for destructive interference. c. 2t=(m+12)λn(m=0,1,2,...) for constructive interference. d. 2t=mλn(m=0,1,2,...) for destructive interference.

State the right hand rule of the direction of magnetic field in a conductor carrying current

Aperson gives a shopping cart an initial push along a horizontal floor to get it moving, and then lets go. the cart travels forward along the floor, gradually slowing as it moves. consider the horizontal force(s) on the cart while it is moving forward and slowing. which of the following statements is correct? (a) both a forward and a backward force are acting on the cart, but the forward force is larger. (b) only a forward force is acting which diminishes with time. (c) both a forward and a backward force are acting on the cart, but the backward force is larger. (d) only a backward force is acting, no forward force.

Explain why electric current cannot exist if a current doesn't have a voltage source.