Mod 3 (Geometrical Optics, Mirrors) – Homework Answers

geometrical optics

study of light propagation in terms of rays,

rectilinear propagation of light

In a homogeneous medium, light travels in straight lines

law of reflection

The angle of incidence (θ₁) = angle of reflection (θ₂),

The incident ray, the reflected ray, and the normal to the surface all lie in the same plane

angle of incidence (θ₁) is measured where

between the incident ray and the normal to the
surface

angle of reflection (θ₂) is measured where

between the reflected ray and the
normal

how does law of reflection determine the behavior of light on a reflective surface

governs how mirrors and other reflective surfaces form images.

refraction

change in direction of a wave (such as light) when it
moves from one medium to another

Light going from a higher refractive index to lower

It travels faster and bends away from normal

Light going from a lower refractive index to higher

travels slower and bends toward normal

Snell’s Law equation

Snell’s Law

allows us to calculate how much light bends between media due to the differences in index
of refraction

How do optical fibers utilize the principle of total internal reflection

guide light through continuous internal reflections, preventing signal loss
while transmitting data efficiently over long distances

characteristics of an image formed in a plane mirror

virtual, upright, laterally inverted, and the same size as the object. The image appears behind the mirror at the same distance as the object is in front

Characteristics concave mirror

curves inward and can produce both real and virtual images.

Characteristics Convex mirror

always forms virtual, upright, and reduced images

focal point (F) of a spherical mirror

where parallel rays converge after reflection

Focal Point location

half the distance between the mirror’s vertex and its center of curvature

If magnification is negative

the image is inverted

If magnification is positive

The image is upright

How does the image formed by a concave mirror change as the object distance approaches
the focal length

the image becomes larger and farther away

Image at focal length of concave

No image

Why do convex mirrors always produce virtual, upright, and reduced images

reflected rays always diverge, appearing to originate from behind the mirror,
making the image virtual and smaller

Why does a real image appear inverted

forms where actual light rays converge

Why does a virtual image appear upright

forms from apparent ray extensions

If a concave mirror produces a real and inverted image, where is the object located relative
to the focal point

beyond the focal point.

why no image is formed when an object is placed exactly at the focal point of a
concave mirror

reflected rays become parallel, meaning they never converge

How does increasing the curvature of a spherical mirror affect its focal length

decreases the radius of curvature, making the focal length shorter.