Exam 23: Mirrors and Lenses

A compound microscope has a 18-cm-long barrel and an objective lens with a focal length of 8.0 mm.What is the focal length of the eyepiece to give a total magnification of 240? It is adjusted for minimum eyestrain for persons with a near point of 25 cm.

A convex lens has focal length f.If an object is located at "infinity" (very far away),the image formed is located at a distance from the lens

If you stand in front of a convex mirror,at the same distance from it as its radius of curvature,

An object is 5.7 cm from a spherical concave mirror.If the image is 4.7 cm tall and 10 cm from the mirror,how tall is the object?

A magnifying glass uses a convex lens with a refractive power of 20 diopters.What is the angular magnification if the image is to be viewed by a relaxed eye with a near point of 25 cm?

If a spherical concave mirror has a radius of curvature R,its focal length is

The length of the telescope is 1.60 m,and it has a magnification of 60.0.What is the focal length of the objective lens?

The image formed by a single concave lens

A seed is 15 mm in front of a convex lens,and the image of the seed is 4.0 mm behind the lens.What is the focal length of the lens?

A machinist with normal vision has a near point at 25 cm.This machinist wears +4.25-diopter eyeglasses in order to do very close work.With these eyeglasses,what is the near point of the machinist? Assume that he wears the glasses extremely close to his eyes.

An object that is 75 cm tall is located 3.8 m in front of a plane mirror.The image formed by the mirror appears to be

The objective lens and the eyepiece of a microscope have focal lengths of 4.0 mm and 25 mm,respectively.The objective produces a real image 30 times the size of the object,with the final image viewed at infinity.The near point of the microscope user is at 25 cm.What is the distance between the objective lens and the real image that it produces?

Which of the following statements about spherical mirrors is correct? (There could be more than one correct choice.)

A convex lens has focal length f.If an object is placed at a distance beyond 2f from the lens on the principal axis,the image is located at a distance from the lens

Which one of the following is normally not a characteristic of a simple two-lens refracting astronomical telescope?

A person is nearsighted with a far point of 75.0 cm. (a)What focal length contact lens is needed to give him normal vision? (b)What is the power of the corrective lens?

The distance between the object to be viewed and the eyepiece of a compound microscope is 25.0 cm.The focal length of its objective lens is 0.200 cm and the eyepiece has a focal length of 2.60 cm.What is the magnitude of the total magnification of the microscope when used by the person of normal eyesight if it is designed for minimum eyestrain?

When a person with a near point at 28 cm uses a certain magnifying glass,it produces an angular magnification of 7.0 with the image very distant.What is the focal length of the lens of this magnifying glass?

For an eye that is 2.4 cm in diameter,what must be the range of focal lengths of the lens to focus objects from the near point (25 cm)to infinity on the retina?

A beam of light that is parallel to the principal axis strikes a convex mirror.What happens to the reflected beam of light?