## Question

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):

### Solution

#### SIMILAR QUESTIONS

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:

A short linear object of length *L* lies on the axis of a spherical mirror of focal length *f* at a distance *u* from the mirror. Its image has an axial length*L’* equal to:

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:

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:

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 slide projector gives a magnification of 10. If it projects a slide of dimensions 3 cm × 2 cm on a screen, the area of the image on the screen will be:

An equiconvex glass lens (a) has a focal length *f* and power *P*. It is cut into two symmetrical halves (b) by a plane containing the principal axis. The two pieces are recombined as shown in fig. (c) The power of new combination is: