Physics Lab Exam 1 Flashcards
convex lens
a converging lens
what is the thin lens and what is it used for
1/do + 1/di = 1/f
- do = object distance or the distance between the object and the lens
- di = the distance between the image and the lens
- f = focal length, the potin at which light rays converge
what is the ray model of light
modeled as traveling in straight linesre
refraction
when light passes from one medium to another medium the light rays will bend because light travels at different speeds in each medium
what is n in regards to refraction
the index of refraction which measures how much the medium affects the speed of the light passing through the medium
what do larger values of n indicate
that the medium is more dense and the n value would be greater than that of air which is 1
characteristics of converging lenses
- thicker in the center than at the edges
- refracts parallel rays towards the optical axis
what sign is the focal length for converging lenses
positive
what is 1/f also known as
the power
equation for magnification
- (di/do)
what do negative numbers of magnification indicate
indicates inverted image is produces
what do larger magnitudes of magnification indicate
how much bigger the image is than the object
what happens when the object is loacted very far from the lens
do will basically be zero so the object distance can be used to find the focal length or vice versa
what is a real image when using converging lenses
when the object is farther from the lens than the focal length and the image produced is on the side of the outgoing light
when is a vritual image formed when using converging lenses
when the object is closer from the lens than the focal length
- image wont be projected on a screen it would be shown on the side of the lens
what happens if an object is placed at the focal point
the image produced is at infinity and no image will be produced
what does a 1/di vs 1/do plot illustrate
shows the relationship between the two images, and the focal point can be determined by the x-intercept as 1/do would be 1/f
can a diverging lens produce a real image
no
what image is produced when the object is placed further from the focal point using a diverging lens
it will be smaller and in between the focal point and the lens
what image is produced when the object is placed closer to the lens
a larger virtual image will be produced
how are images formed with the eye
light rays enter the eye and the lens helps to focus the rays onto the retina
how does the eye focus images
the eye can change the shape of the lens and therefore change the focal length
for normal vision what is the far point
infinity
what is a far point
the furthest distance at wich an object can be placed and still be seen clearly by the eye
what is a near point
the closest distance where an object can be placed and still form a clear image
what is hyperopia or farsightedness
- inability to see close objects clearly while distant objects may be clear
- cannot converge rays enough where it can hit the retina (image formed behind the eye)
what is the cause of farsightedness
eyeball is too short
what is the near point for someone with farsightedness
NP > 25 cm
how do you fix farsightedness
using a converging lens which can form a virtual image at the eyes NP and produce an image
what is myopia or nearsightedness
can produce images of close objects not far objects
- objects that are farther come to focus in front of the retina
what is the cause of nearsightedness
the eye is too long
what is the correction for nearsightedness
use a diverging lens to defocus the rays and allow the rays to focus on the retina
what is a negative power lens
lens that is used for nearsightedness (diverging) lenses
