PLANE MIRROR

PLANE MIRROR

Any smooth, highly polished reflecting surface is called a mirror. A plane mirror is a highly polished plane surface.

CHARACTERISTICS OF IMAGE FORMED BY PLANE MIRRORS:

Following are the important characteristics of image formed by plane mirrors.

Ex. If the object moves with a velocity 'u' then the image moves with velocity 2u.how?

Solution: Detailed explanation is here: Distance of Image formed in the mirror is same as the distance of the object form thesurfaceof the mirror.

Thus is distance of object = u

Then distance of image = -u (as the image is formed at othersideof the mirror)

Thus distance between image and object = 2u ...(1)

Now if mirroe is approaching you/object with speed v, then distance travelled by mirror in unit time = v units

Thus distance between mirror and object in unit time = u - v

Thus disatnce between object and its image = 2(u-v)....(2)

From equations (1) and (2) distance between image and object isreducedby 2v units in unit time(1 second)

Thus speed of image w.r.t object = 2v

Image formation by a plane mirror

1. The image formed in a plane mirror is always virtual. Such an image cannot be taken on a screen.
2. The image formed in a plane mirror is always erect. It is the same side up as the object.
3. The image in a plane mirror is of the same size as the object.
   
4. Diagram to show lateral inversion
5. The image formed by a plane mirror is at the same distance behind the mirror as the object is in front of the mirror i.e. Image distance is always equal to the object distance in a plane mirror.
6. The image formed in a plane mirror is laterally inverted i.e. the left side of the object becomes the right side of the image and vice-versa.

QUESTIONS 1. A ray of light hits a plane mirror and bounces off of the mirror. Which light ray is the incident ray?

QUESTIONS 2. A ray of light hits a plane mirror and bounces off of the mirror. Which light ray is the reflected ray?

QUESTIONS 3.The normal to a mirror line can be described as:

QUESTIONS 4. If the angle of incidence in a plane mirror is 15 degrees, what will be the angle of reflection?

QUESTIONS 5. How do you find the location of the image in a plane mirror?

ANSWER:

Solution 1. The light ray approaching the mirror

Solution 2. The light ray bouncing off the mirror

Solution 3. A 90 degree line to the mirror

Solution 4. The angle of reflection is equal to the angle of incidence. 15degrees

Solution 5. It is located on theback sideof the mirror where all the reflected rays come together

SPHERICAL MIRRORS:

A mirror whose reflecting surface is a part of a hollow sphere is known as spherical mirror. For example, a dentist uses a curved mirror to examine the teeth closely, large curved mirrors are used in telescope at observatories.

These are of the type convex and concave.

Related Topics

• Mirror Formula
• Images
• Laws of Reflection