Ray Optics and Optical Instruments

Related Questions

• A convex lens makes a real image 4 cm long on a screen. When the lens is shifted to a new position without disturbing the object, we again get a real image on the screen which is 16 cm tall. The length of the object must be

  ---

• A satisfactory photographic print is obtained when the exposure time is 10 sec at a distance of 2 m from a 60 cd lamp. The time of exposure required for the same quality print at a distance of 4 m from a 120 cd lamp is

  ---

• The wavelength of emission line spectrum and absorption line spectrum of a substance are related as

  ---

• The image distance of an object placed 10 cm in front of a thin lens of focal length + 5 cm is

  ---

• A point object is placed at the center of a glass sphere of radius 6 cm and refractive index 1.5. The distance of the virtual image from the surface of the sphere is

  ---