Lenses Flashcards
What is a converging lens?
A converging lens bends light inward as light passes through it.
What is a diverging lens?
A diverging lens bends light outward as light passes through it.
What type of image do both concave and convex lenses produce?
Both produce a virtual image where light rays diverge from a point after passing through a lens.
What is a magnifying glass?
A convex lens that produces an enlarged and upright image.
The enlarged image lies on the same side as the object.
What does a camera do?
A camera produces a real but diminished image of an object on light-sensitive film.
What does a slide projector do?
A slide projector produces a real and enlarged image of a slide on a screen.
What is the function of a telescope?
A telescope uses two lenses to magnify the image of a distant object.
What is Linear Magnification (m)?
The factor by which an object is magnified by the lens.
m = image height / object height OR image distance / object distance
What is the Lens Formula?
1/f = 1/v + 1/u
Where f is the focal length, v is the image distance, and u is the object distance.
What are the possible effects on image size compared to the object?
Magnified, equal size, or diminished.
What is a Virtual Image?
An image observed at a point from which rays seem to come from.
What is a Real Image?
An image formed where light rays actually meet.
An image will be formed on a screen placed at this point
What happens when a screen is placed at the point of a Real Image?
An image will be formed on a screen placed at this point.
What produces virtual images?
A magnifying glass, plane mirror, and spectacles used for correcting long and short sight.
What focuses real images?
A screen placed behind a magnifying glass in front of an open window, the film of a camera, the retina of the eye, and the screen used with a projector.
What are the characteristics of virtual images?
Cannot be formed on a screen, are not formed by the intersection of real rays, are erect, and are on the same side of the lens as the object.
What are the characteristics of real images?
May be formed on a screen, are formed by the intersection of real rays, are inverted, and are on the opposite side of the lens.
What is the cornea?
The tough transparent part of the eye, at the front of the eye.
What is the sclera?
The white, tough part of the eye.
What is the iris?
The coloured part of the eye, which surrounds the pupil controlling the amount of light entering the eye.
What is the pupil?
The dark hole in the middle of the eye, it allows the eye to adjust different light intensities.
What is the lens?
A bi-concave converging lens of a jelly-like, flexible and transparent material.
What is the retina?
The light sensitive part of the eye, made up of rods and cones. This is where the images are formed.
What is the choroid?
Supplies the eye with blood, and reduces reflection within the eye.
