Exam 24: Optical Instruments

The distance between the object 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. A person with a near point of 25.0 cm and a far point at infinity is using the microscope. (a) What is the angular magnification obtainable using the eyepiece alone as a magnifying lens if the final image is at the person's far point? (b) What is the total magnification of the microscope when used by the person of normal eyesight?

You have available lenses of focal lengths 2.0 cm, 4.0 cm, 8.0 cm, and 16.0 cm. (a) If you were to use any two of these lenses to build a telescope, what is the maximum magnification you could achieve? (b) If you were to use any two of these lenses to build a telescope, what is the lens separation for the maximum magnification telescope?

The near point of a farsighted person's uncorrected eyes is 80 cm. What power contact lens should be used to move the near point to 25 cm from this person's eyes?

A lens is designed to work in the visible, near-infrared, and near-ultraviolet. The best resolution of this lens from a diffraction standpoint is

A person's eye lens is 2.7 cm away from the retina. This lens has a near point of 25 cm and a far point at infinity. (a) What must the focal length of this lens be in order for an object placed at the near point of the eye to focus on the retina? (b) What must the focal length of this lens be in order for an object placed at the far point of the eye to focus on the retina?

The eyepiece of a compound microscope has a focal length of 2.50 cm and the objective has a focal length of 1.60 cm. The two lenses are separated by 15.0 cm. The microscope is used by a person with normal eyes (near point at 25 cm). What is the angular magnification of the microscope?

The angular magnification of a refracting telescope is 40 x. When the object and final image are both at infinity, the distance between the eyepiece and the objective is 143.5 cm. The telescope is used to view a distant radio tower. The real image of the tower, formed by the objective, is 6.0 mm in height. The focal point of the eyepiece is positioned at the real image. What is the focal length of the objective lens?

Light of wavelength 633 nm from a He-Ne laser passes through a circular aperture and is observed on a screen 4.0 m behind the aperture. The diameter of the central bright area is 5.4 cm. What is the diameter of the aperture?

A man is nearsighted and cannot see things clearly beyond 110from his eyes. What is the focal length of the contact lenses that will enable him to see very distant objects clearly?

What is the limiting angle of resolution for the eye if the pupil diameter of the eye is 4.0 mm, the wavelength of the light is 600 nm, and index of refraction of the liquid in the eye is 1.34?

If the diameter of a radar dish is doubled, what happens to its resolving power assuming that all other factors remain unchanged?

A simple refracting telescope provides large magnification by employing

In a 35.0-mm single lens reflex camera (SLR), the distance from the lens to the film is varied in order to focus on objects at varying distances. Over what distance range must a lens of 55-mm focal length vary if the camera is to be able to focus on objects ranging in distance from infinity down to 0.60 m from the camera?

What power contact lens must be used to correct the vision of a nearsighted person whose far point is 40 cm?

The angular magnification of a refracting telescope is 40 x. When the object and final image are both at infinity, the distance between the eyepiece and the objective is 143.5 cm. The telescope is used to view a distant radio tower. The real image of the tower, formed by the objective, is 6.0 mm in height. The focal point of the eyepiece is positioned at the real image. What is the angle subtended by the final image of the tower.

The focal lengths of the objective 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 (with the eye focused at the far point). The near point of the person using the microscope is 25 cm and the far point is at infinity. What is the final overall magnification of the microscope?

A person having a near point of 25 cm and a far point at infinity uses a converging lens of focal length 5.0 cm as a magnifying glass. What is the magnification if the person's eye is relaxed (with the image at his far point)?

A nearsighted person has her distant vision corrected using a -2.0-diopter contact lens. Her uncorrected near point is 15 cm. What is her near point using this lens if the lens is 2.0 cm from the eye?

Which one of the following is a characteristic of a compound microscope?

A 10-inch telescope (25.4 cm in diameter) is used to determine if what appears to be one star is actually two stars. Stars are so far away that they are essentially point sources. How close (in angle) can the two stars be and still be resolved by this telescope if it is focusing light of wavelength of 550 nm? (Consider only the limitation due to diffraction.)