Advertisements
Advertisements
Questions
A straight stick partly dipped in water obliquely appears to be bent at the surface of the water.
A rod immersed partially and obliquely in water appears to be bent. Explain.
Advertisements
Solution 1
The phenomenon is due to refraction of light.
A ray of light OC coming from O passes from water into air and is refracted away from normal (along CX). Another ray, OD, gets refracted along with DY. The two refracted rays CX and DY, when produced backwards, appear to meet at the point I. Thus, I is the virtual image of the end O of the stick. Therefore, the stick appears to be bent as shown below.
Solution 2
- Light Refraction: When light passes from one medium (e.g., water) to another (e.g., air), it changes speed and direction. Light rays traveling from the submerged part of the stick (in water) to the observer's eyes (in air) bend away from normal at the water’s surface.
- Apparent Bending: Due to this bending of light, the part of the stick underwater appears shifted upward. As a result, the stick seems bent at the surface of the water, even though it is straight.
RELATED QUESTIONS
An image that cannot be obtained on a screen is called ______.
Define Radius of curvature of the spherical mirror
What happens when a ray of light falls normally (or perpendiculary) on the surface of a plane mirror?
What kind of mirror is required for obtaining a virtual image of the same size as the object?
A lens forms a real image 3 cm high of an object 1 cm high. If the separation of object and image is 15 cm, find the focal length of the lens.
A small object is placed 150 mm away from a diverging lens of focal length 100 mm.
(i) Copy the figure below and draw rays to show how an image is formed by the lens.
Figure
(ii) Calculate the distance of the image from the lens by using the lens formula.
Explain the following terms :
Pole, Centre of curvature, Radius of curvature, Principal axis. Show them on separate diagrams for each of the concave and convex mirrors.
State the direction of incident ray which after reflection from a spherical mirror gets reflected along its own path. Give a reason.
Draw suitable diagrams to illustrate the action of (i) concave mirror and (ii) convex mirror on a beam of light incident parallel to the principal axis.
How will you distinguish between a plane mirror, a concave mirror and a convex mirror, without touching them?
Define the following term in relation to concave mirror.
Aperture
What is the relation between focal length and radius of curvature of a concave mirror?
Define the term Aperture.
The following Figure shows a concave mirror MM' on which a ray of light incident from a point P gets reflected to meet the principle axis at O.
(a) Find, by construction, the position of the centre of curvature of the concave mirror.
(b) Write down the value for the radius of curvature of the mirror.
(c) Calculate the focal length of the mirror.
(d ) Which relation is used in deducing the focal length from the radius of curvature?
The spherical mirror with a reflecting surface curved inward is called
Define focal length.
A shopkeeper wanted to fix a mirror which will give a maximum view of his shop. What type of mirror should he use? Give reason.
The image formed in a plane mirror is always inverted.
Explain why a ray of light passing through the center of curvature of a concave mirror, gets reflected along with the same pattern.
