Exam 19: Optical Instruments

A lens of focal length 90 mm is used as a magnifier.The object being viewed is 9.9 mm long,and is positioned at the focal point of the lens.The angle subtended by the image at infinity,in milliradians,is closest to:

Situation 19.2 The objective 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.The final image is viewed at infinity.The near point of the microscope user is at 25 cm. -In Situation 19.2,the distance between the objective and the real image produced by it,in mm,is closest to:

A nearsighted person requires glasses with diverging lens to read.

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 14.0 cm.The microscope is used by a person with normal eyes (near point at 25 cm).What is the angular magnification of the microscope?

A simple camera lens with focal object length f_o = 3.00 cm perfectly focuses the image of an object on a photographic film located a distance 14.00 cm away from the lens.The object now moves away from the lens and the new focal distance is 13.00 cm. (a)How far did the object move? (b)What is the new magnification?

A lens of focal length 40 mm is mounted on a 35 mm camera.The lens aperture is set at f/5.6 and the shutter speed set at 1/250 s.A different camera has a lens of focal length 56 mm in place.The shutter speed is set at 1/60 s.The lens aperture setting,for the closest matching film exposure,is:

Situation 19.2 The objective 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.The final image is viewed at infinity.The near point of the microscope user is at 25 cm. -In Situation 19.2,the overall magnification of the microscope is closest to:

In a 35 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 range must a lens of 45 mm focal length vary if the camera is to be able to focus on objects ranging in distance from infinity down to 1.4 m from the camera?

Situation 19.3 The angular magnification of a refracting telescope is 40.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. -In Situation 19.3,the focal length of the objective,in cm,is closest to:

As a treatment for cataracts (a cloudiness of the lens of the eye),the natural lens is removed and a plastic lens is implanted.After this is done a person can see distant objects clearly,but he cannot accommodate to focus on nearby objects.If for example such a person wanted to read a book at a distance of 25 cm,he would have to wear eyeglasses whose diopter power was approximately

A lens of focal length 40 mm is used as a magnifier.The object being viewed is 5.3 mm long,and is positioned at the focal point of the lens.The user of the magnifier has a near point at 25 cm.The angular magnification of the magnifier is closest to:

A myopic girl wears eyeglasses that allow her to have clear distant vision.The power of the lenses of her eyeglasses is - 3.00 diopters.Without eyeglasses,the far point of the girl is closest to:

If red light and violet light both strike and enter a sheet of glass at the same angle with respect to the normal,the violet light will be deflected from its original direction more than the red light will.

In a compound microscope