Questions in Ray Optics and Optical Instruments

SelectQuestion
A thin glass (refractive index $1.5$) lens has optical power of $-\,5D$ in air. It's optical power in a liquid medium with refractive index 1.6 will be
The plane faces of two identical plano-convex lenses each having focal length of 40 cm are pressed against each other to form a usual convex lens. The distance from this lens, at which an object must be placed to obtain a real, inverted image with magnification one is
If two lenses of +5 diopters are mounted at some distance apart, the equivalent power will always be negative if the distance is
A concave lens and a convex lens have same focal length of 20 cm and both put in contact this combination is used to view an object 5 cm long kept at 20 cm from the lens combination. As compared to object the image will be
The focal length of the field lens (which is an achromatic combination of two lenses) of telescope is 90 cm. The dispersive powers of the two lenses in the combination are 0.024 and 0.036. The focal lengths of two lenses are
A combination of two thin lenses of the same material with focal lengths ${{f}_{1}}$ and ${{f}_{2}}$, arranged on a common axis minimizes chromatic aberration, if the distance between them is
If the focal length of a double convex lens for red light is ${{f}_{R}},$ its focal length for the violet light is
A thin equiconvex lens is made of glass of refractive index 1.5 and its focal length is 0.2 m, if it acts as a concave lens of 0.5 m focal length when dipped in a liquid, the refractive index of the liquid is
The dispersive power of the material of lens of focal length 20 cm is 0.08. The longitudinal chromatic aberration of the lens is
Which source is associated with a line emission spectrum

View Selected Questions (0)

Back to Categories

Back to Home