## Question

A double convex lens of focal length 6 cm is made of glass of refractive index 1.5. The radius of curvature of one surface is double that of the other surface. The value of smaller radius of curvature is:

### Solution

4.5 cm

Solving, we get *R* = **4.5 cm.**

#### SIMILAR QUESTIONS

Time taken by sunlight to pass through a window of thickness 4 mm whose refractive index is 1.5 is:

A ray of light is incident on the surface of separation of a medium with the velocity of light at an angle 45^{o} and is refracted in the medium at an angle 30^{o}. What will be the velocity of light in the medium

A ray of light falls on a transparent glass slab with refractive index (relative to air) of 1.62. The angle of incidence for which the reflected and refracted rays are mutually perpendicular is:

A concave mirror of focal length *f* produces an image *n* times the size of the object. If the image is real, then the distance of the object from the mirror is:

A convex mirror of focal length *f* produces an image (1/n)*th* of the size of the object. The distance of the object from the mirror is:

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A thin convergent glass lens (μ_{g} = 1.5) has a power of +5.0 D. When this lens is immersed in a liquid of refractive index it acts as a divergent lens of focal length 100 cm. The value of *μ _{l}* must be:

The sun (diameter = *D*) subtends an angle of θ radians at the pole of a concave mirror of focal length *f*. The diameter of the image of the sun formed by the mirror is:

Diameter of a plano-convex lens is 6 cm and thickness at the centre is 3 mm. If the speed of light in the material of the lens is , the focal length of the lens is:

A luminous point is moving at speed *v _{0}* towards a spherical mirror, along its axis. Then the speed at which the image of this point object is moving is given by (with

*R*= radius of curvature and

*u*= object distance):