Topic 5/6: Geometric Optics, Reflection, Refraction/ Wave optics, Microscopy, Resolution Flashcards
What is refraction?
the change of direction of a wave when passing through an interface
What does Fermat’s principle state?
it states that when moving from point A to point B, light takes the path that takes the least time
The degree to which light bends depends on…..
the index of refraction
What is Snell’s law?
sinα/sinβ= c1/c2 α is the incident angle while β is the angle of refraction
What is total internal reflection?
when the incident ray hits the new substance at an angle greater than the critical angle, most of the light will refract back into the original medium and not go to the next one
What is the incident angle?
the angle between the incident ray and the normal
What is grazing ray?
when the incidence angle approaches 90 degrees
What is the critical angle?
when the incidence angle is a grazing ray meaning it is 90 degrees- will have the largest possible angle of refraction
What is a focal point?
point where refracted rays converge at a point on the optical axis of the lens
What is the focal length?
the distance from the lens to the focal point
What is the lens makers equation?
D=1/f it gives the power of the lens in diopters, f is the focal length
What is magnification?
the ratio showing how much bigger the image is compared to the object size
What is resolution?
the smallest distance between observed points- detailed visibility
How is resolution calculated?
with ABBE’S EQUATION
What is Abbe’s principal?
the grating period is proportional to the size of the details that may be resolved
