Geometrical OpticsHard
Question
An eye specialist prescribes spectacles having combination of convex lens of focal length 0 cm in contact with a concave lens of focal length 25 cm. The power of this lens combination is diopters is
Options
A.+ 1.5
B.- 1.5
C.+ 6.67
D.- 6.67
Solution
The focal length of combination is given by
or
cm = - 
∴ Power of the combination in dioptres,
P = - 
= - 1.5
or
cm = - ∴ Power of the combination in dioptres,
P = -
= - 1.5
Create a free account to view solution
View Solution FreeMore Geometrical Optics Questions
For a normal eye, the cornea of eye provides a converging power of 40 D and the least converging power of the eye lens b...The distance of an object from a spherical mirror is equal to the focal of the mirror. Then the image :...In a double slit experiment instead of talking slits of equal widths, one slits is made twice as wide as the other, then...An object is placed on the axis of a convex lens. Its image is formed 80 cm from the object. The magnification is 3. The...The time taken by sunlight to cross a 5 mm thick glass plate (μ = 3/2) is...