A beam of light strikes a soap film. Fig. 5.1 gives an enlarged view of a tiny section of the soap film. As the beam enters the soap film, it is refracted. The diagram shows air above, soap film, and air below, with an incident angle of $30^{\circ}$. The refractive index of the soap film is 1.28.
(a)[1]
Define refractive index in relation to the speed of light.
(b(i))[2]
Show that the angle of refraction as the light enters the soap film is about $43^{\circ}$.
(b(ii))[2]
On Fig. 5.1, draw the refracted light ray in the soap film with care and add a label for the angle of refraction.
(c(i))[1]
Define the term monochromatic.
(c(ii))[3]
Calculate the frequency of the light.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Refractive index is the quotient of the speed of light in two separate media OR speed of light in air \div speed of light in (soap) film” …