Exam 23: Mirrors and Lenses

An object is in front of a concave spherical mirror,and its image is 4.0 cm behind the mirror.If the focal length of the mirror has a magnitude of 5.0 cm,where is the object?

The focal length of the lens of a simple film camera is 40.0 mm.By what amount should the distance between the lens and the film be increased or decreased to change the focus from a person who is 25 m from the lens to one who is 4.0 m from the lens?

A plant that is 4.1 cm tall is 10.3 cm from a convex lens.You observe that the image of this plant is virtual and 6.2 cm tall.What is the focal length of the lens?

Diego is nearsighted and cannot see things beyond 110 cm from his eyes.What is the focal length of the contact lenses that will enable him to comfortably see distant hills clearly?

An object is placed in front of a thin lens.Which statements are correct in describing the image formed by the lens? (There could be more than one correct choice.)

Starting from very far away,an object is moved closer and closer to a convex lens,eventually reaching the lens.What happens to its image formed by that lens? (There could be more than one correct choice.)

The focal length of a magnifying glass is 15 cm.If the near point of a person is 25 cm,what is the angular magnification of the glass for this person when his eyes are focused at infinity?

The objective lens of a refracting astronomical telescope has a focal length of 60 cm,and the eyepiece has a focal length of 2.0 cm.How far apart should the lenses be placed in order to form a final image at infinity?

The distance between the object to be viewed and the eyepiece of a compound microscope is 18.0 cm.The focal length of its objective lens is 0.80 cm and the eyepiece has a focal length of 2.3 cm.The near-point distance of the person using the microscope is 25.0 cm.What is the magnitude of the total magnification of the microscope if it is designed for minimum eyestrain?

An object that is 4.0 cm tall is placed 15 cm in front of a concave mirror of focal length 20 cm. (a)Where is the image formed and how far is it from the mirror? (b)How tall is the image?

How far from a covnex lens of focal length 30 cm must an object be placed so the image will be virtual and 3.0 times as large as the object?

A 4.0-cm-tall object is placed 50.0 cm from a concave lens having a focal length of magnitude 25.0 cm.What is the nature and location of the image?

The objective lens of a telescope has a focal length of 2.0 m and its eyepiece has a focal length of 1.0 cm.What is the magnification of this telescope when viewing Jupiter?

The focal length of a convex mirror is has a magnitude of 20 cm.What is its radius of curvature?

Olga is nearsighted and cannot see things beyond 90 cm cm from her eyes.What is the refractive power of the contact lenses that will enable her to comfortably see distant buildings clearly?

A concave mirror having a focal length of magnitude 5.0 cm forms an image 4.0 cm behind the mirror.Where is the object for this image?

A nearsighted man wears contact lenses of -3.00 diopters.With these lenses,his corrected near point is 25.0 cm.What is his uncorrected near point?

A person is designing a telescope with a magnification of 10.If the telescope is limited to a length of 0.20 m,what is the approximate focal length of the objective?

An object that is 3.4 mm tall is placed 25 cm from the vertex of a convex spherical mirror.The radius of curvature of the mirror has magnitude 73 cm. (a)How far is the image from the vertex of the mirror? (b)What is the height of the image?

The focal lengths of the objective lens and the eyepiece in a microscope are 0.29 cm and 2.50 cm,respectively.An object is placed at 0.30 cm from the objective lens and the image of this object is viewed with the eyepiece adjusted for minimum eyestrain for persons with a near point of 25 cm.The magnitude of the final overall magnification of the microscope is closest to