Question

State two uses of concave mirror.

Answer 1

Hint: In case of mirrors usually there are three types used - Plain mirror, concave mirror and convex mirror. All will serve different purposes. Properties of different mirrors are different. In case of convex mirrors they always form virtual images. While concave mirrors form both virtual and real images and plain mirrors form virtual images.

Complete step-by-step answer:
Various positions of placing an object in front of a concave mirror gives us various positions of images.
If an object is placed between the pole and focus of the concave mirror then image will be formed on the other side of the mirror. That image formed can be enlarged or diminished and virtual.
Now if we place an object between focus and center then the image is formed away from the center and the image will be real and inverted. The size of the image will be bigger than an object as shown in the diagram.

If the object is placed exactly at center the image also will be formed exactly at the center just as shown in the diagram below.

P denotes the pole and F denotes the focus and C denotes the center.
The uses of concave mirrors are as follows-
In case of dentists
They use concave mirrors because when an object is placed between the pole and focal length of this mirror this forms a virtual enlarged image. Hence magnified image means a more clear view of a part where the doctor wants to examine.

Flood lights
In flood lights we use concave mirrors and the light bulb is kept nearly at the center of the concave mirror and the light from bulb reflets from that concave mirror and provides higher uniform intensity.

Solar devices having mirrors
Concave mirrors are used in solar devices because they can harness sunlight that means they focus sun rays to a particular focal point and a bowl is kept there to heat in case of solar cookers. The solar energy present at that point can melt salt too.

Note: The reason why we use concave mirrors in floodlights is because it can focus the rays of flood light onto exactly at a particular point and energy is utilized effectively. In case of solar cooking devices the rays coming from infinite distance will focus exactly at the focal length and the cooking vessel is kept at that focal length so that food will be cooked easily due to that heat.