Snell's law determines how sharply the rays bend
Any ray passing through the near focal point emerges as a parallel ray
The focal length of a converging lens is:
A. the distance from the object where an image is formed
B. the distance at which an object must be placed to form an image
C. the distance from the lens plane at which parallel light rays are focused
D. the distance from the front surface of the lens to its back surface
E. the point at which light is focused inside the lens
The thin lens equation relates the focal length, f, to the object distance, s, and the image distance, s'.
A 4.0 cm high object is 150 cm from the focal point a 50 cm lens of a camera.
How far should the film be placed behind the lens to record a focused image?
What is the size of the image on the film?
Draw the ray diagram to show the image.
Note that the image is inverted. What is the magnification?
Notice that your object is more than two focal lengths from the lens.
Which of the following statements is true, concerning a double convex lens?
A. A real image is formed if s < f, a virtual image is formed for s > f
B. A virtual image is formed if s < f, a real image is formed for s > f
C. A real image is always formed
D. A virtual image is always formed
A diverging lens with a focal length of 50 cm is placed 100 cm from an object.
Draw the principle rays
Ray diagrams - summary
The second lens in this optical instrument
A. Causes the light rays to focus closer than they would with the first lens acting alone
B. Causes the light rays to focus farther away than they would with the first lens acting alone
C. Inverts the image but does not change where the light rays focus
What happens to the image if you cover the top half of a converging lens? (Assume the object is much farther away than 2 focal lengths.)
A. The top half of the image will disappear.
B. The bottom half of the image will disappear.
C. The whole image will appear but will be dimmer.
D. The whole image will appear but it will be blurry.
E. The image will be the same as if the top of the lens was uncovered.