Advertisements
Advertisements
प्रश्न
Use the mirror equation to deduce that an object placed between the pole and focus of a concave mirror produces a virtual and enlarged image.
Advertisements
उत्तर
For a concave mirror, the focal length (f) is negative.
∴ f < 0
When the object is placed on the left side of the mirror, the object distance (u) is negative.
∴ u < 0
It is placed between the focus (f) and the pole.
∴ f > u > 0
`1/"f" < 1/"u" < 0`
`1/"f" - 1/"u" < 0`
For image distance v, we have the mirror formula:
`1/"v" + 1/"u" = 1/"f"`
`1/"v" = 1/"f" - 1/"u"`
∴ `1/"v" < 0`
∴ v > 0
The image is formed on the right side of the mirror. Hence, it is a virtual image.
For u < 0 and v > 0, we can write:
`1/"u" > 1/"v"`
v > u
Magnification, m = `"v"/"u" > 1`
Hence, the formed image is enlarged.
संबंधित प्रश्न
Calculate the distance of an object of height h from a concave mirror of radius of curvature 20 cm, so as to obtain a real image of magnification 2. Find the location of the image also.
Give two reasons to explain why a reflecting telescope is preferred over a refracting telescope.
Use the mirror equation to show that a convex mirror always produces a virtual image independent of the location of the object.
Using mirror formula, explain why does a convex mirror always produce a virtual image.
A point object O is placed at a distance of 15cm from a convex lens L of focal length 1 Ocm as shown in Figure 5 below. On the other side of the lens, a convex mirror M is placed such that its distance from the lens is equal to the focal length of the lens. The final image formed by this combination is observed to coincide with the object O. Find the focal length of the convex mirror
A point source of light is placed in front of a plane mirror.
Mark the correct options.
Which of the following (referred to a spherical mirror) do (does) not depend on whether the rays are paraxial or not?
(a) Pole
(b) Focus
(c) Radius of curvature
(d) Principal axis
A light ray falling at an angle of 45° with the surface of a clean slab of ice of thickness 1.00 m is refracted into it at an angle of 30°. Calculate the time taken by the light rays to cross the slab. Speed of light in vacuum = 3 × 108 m s−1.
A small object is placed at the centre of the bottom of a cylindrical vessel of radius 3 cm and height 4 cm filled completely with water. Consider the ray leaving the vessel through a corner. Suppose this ray and the ray along the axis of the vessel are used to trace the image. Find the apparent depth of the image and the ratio of real depth to the apparent depth under the assumptions taken. Refractive index of water = 1.33.
Find the angle of deviation suffered by the light ray shown in figure. The refractive index μ = 1.5 for the prism material.
Name the physical principle on which the working of optical fibers is based.
The focal length f is related to the radius of curvature r of the spherical convex mirror by ______.
When a clock is viewed in a mirror, the needles exhibit a time which appears to be 8:20. Then the actual time will be:
An upright object is placed at a distance of 40 cm in front of a convergent lens of a focal length of 20 cm. A convergent mirror of focal length 10 cm is placed at a distance of 60 cm on the other side of the lens. The position and size of the final image will be ______.
A point object is placed at a distance of 30 cm from a convex mirror of a focal length of 30 cm. What is the separation between the image and the object?
A convex lens of focal length 15 cm is placed coaxially in front of a convex mirror. The lens is 5 cm from the pole of the mirror. When an object is placed on the axis at a distance of 20 cm from the lens, it is found that the image coincides with the object. Calculate the radius of curvature of the mirror - (consider all-optical event):
