Advertisements
Advertisements
प्रश्न
An object is placed at a distance of 20 cm in front of a concave lens of focal length 20 cm. find: the magnification of image.
Advertisements
उत्तर
Object distance, u = -20 cm
Focal length, f = -20 cm (concave lens)
For a lens, magnification is
m = `"v"/"u"`
`therefore "m" = (-10)/-20`
∴ m = + 0.5
संबंधित प्रश्न
The following diagram shows an object AB and a converging lens L with foci F1 and F2. Draw two rays from the object AB and complete the diagram to locate the position of the image CD. Also mark on the diagram the position of eye from where the image can be viewed.
The following diagram shows an object AB and a converging lens L with foci F1 and F2 State three characteristics of the image in relation to the object.
Define magnifying power of a simple microscope. How can it be increased?
A magnifying glass forms ______.
An illuminated object lies at a distance 1.0 m from a screen. A convex lens is used to form the image of the object on a screen placed at a distance of 75 cm from the lens. Find:
- the focal length of the lens, and
- the magnification.
Define the term magnifying power of a simple microscope. How does it depend on the focal length of the lens used?
Why is the focal length of the lens, used as a magnifying glass, kept short?
Define magnification produced by a lens. State its unit.
Draw a neat diagram to explain the action of a convergent (convex) lens as a reading glass (or magnifying glass). State the characteristics of the image formed.
What is a magnifying glass (or a simple microscope)? Draw a ray diagram to show how a convex lens may be used as a magnifying glass. Where should the object be placed? State three characteristics of the image formed.
