Uses of Convex Mirrors
We saw that, image formed by convex mirrors is
| Position of the object | Position of the image | Size of the image | Nature of the image |
| At infinity |
At the focus F,
behind the mirror |
Highly diminished,
point-sized |
Virtual and erect |
|
Between infinity
and the pole P of the mirror |
Between P and F,
behind the mirror |
Diminished | Virtual and erect |
So, we see that Convex Mirrors always give diminished and erect image
These mirrors are used as
Rear View Mirror for Vehicles
They are used by drivers to see back side while driving
A convex mirror is used as a rear-view mirror because
the image provided by a convex mirror is
Erect - Hence, the image produced to the driver is not inverted, it’s right side is up.
Diminished - Hence, the image produced is much smaller than the actual size of the object. This helps in providing a wider field of view.
Shop Security Mirrors
Shopkeepers install convex mirrors at different places on their shop
This help them keep track of thieves and shoplifters
Since these mirrors give wide field of view, a large portion of shop can be seen with the help of a single mirror
Use of Concave Mirrors
We saw that, image formed by concave mirrors is
|
Position of the
object |
Position of the
image |
Size of the
image |
Nature of the
image |
| At infinity | At the focus F |
Highly diminished,
point-sized |
Real and inverted |
| Beyond C | Between F and C | Diminished | Real and inverted |
| At C | At C | Same size | Real and inverted |
| Between C and F | Beyond C | Enlarged | Real and inverted |
| At F | At infinity | Highly enlarged | Real and inverted |
| Between P and F | Behind the mirror | Enlarged | Virtual and erect |
So, we see that Concave mirror gives
- Enlarged image when object is between pole and focus
- Parallel ray of light when object is placed at focus
-
Converges rays of light at the focus
Now, using these results, we see the uses of Concave Mirrors
Used as Shaving Mirrors and Makeup Mirrors
It is because when they are kept near the face, the face is within the focus of concave mirror
It produces enlarged virtual image of object
Used by Dentist to see larger image of teeth
It is because when they are kept near the patient's teeth, the face is within the focus of concave mirror
It produces enlarged virtual image of patient's teeth so that dentist can see image of teeth easily
Used in torches, beam lights
Light bulb is placed at focus
This produces powerful parallel beam of light. This can be seen at large distance
Used in Solar Furnaces to Produce Heat
They have concave reflector
They concentrate sunlight and reflect it
Hence they convert solar energy into heat energy
Questions
Question 4 Page 168 - Why do we prefer a convex mirror as a rear-view mirror in vehicles?
NCERT Question 8 - Name the type of mirror used in the following situations.
(a) Headlights of a car.
(b) Side/rear-view mirror of a vehicle.
(c) Solar furnace.
Support your answer with reason.
