[Physics Class Notes] on Difference Between Mirror and Lens Pdf for Exam

Lens

Mirror

The Lens is a material made of glass or plastic bounded by two surfaces. It can either be curved at one side or both sides. 

The Mirror implies a glossy surface at one end and produces an Image of an object by reflection. 

A Mirror follows the laws of reflection.

The Lens is a transparent thick material that is shaped in such a manner that it bends the light passing through it. 

It can converge the light Rays onto a specific point or diverge it away from that point.

A Mirror is a reflector that is shiny from one side and reflects the light Rays coming from the object to make it appear as an Image to the other side.

The Lens is of two types viz: Concave Lens and convex Lens.

A Mirror is of three types viz: concave Mirror, plane Mirror, and convex Mirror

A Lens has two focal points namely F and 2F.

A plane Mirror has no focal point.

It forms an Image the same size as that of the object.

A concave Lens is a diverging Lens

A convex Lens is a converging Lens.

A concave Mirror is a converging Mirror A convex Mirror is a diverging Mirror.

Concave Lenses are used as an aid for people having Myopia or nearsightedness.

Convex Lenses are used as an aid for people having Hypermetropia or farsightedness.

Examples of Concave Mirror – shaving/make up Mirror

In streetlights and car headlights

Convex Mirror – Rearview Mirror in two and three-wheelers

The formula for the image formation by the lens is:

[frac{1}{v}-frac{1}{u}=frac{1}{f}]

Where,

v=the distance of image

u=the distance of object

f=focal length

The formula for the image formation by the lens is:

[frac{1}{v}+frac{1}{u}=frac{1}{f}]

Where,

v=the distance of image

u=the distance of object

f=focal length

Image formation for the object placed at infinity:

1. Concave Lens

2. Convex Lens

Sign conventions:

The Ray diagram for the object placed at infinity:

1. Concave Mirror

2. Convex Mirror

Image formation for the object placed at F

1. Concave Lens

2. Convex Lens

Image formation for the object placed at F

Image formation for the object placed between F (focus) and O (optical center)

Image formation for the object placed between F and C

Real-life example:

Whatever we observe around us is because of something called ‘Lens’. Eyes are natural Lenses that help us to read, write, watch movies, distinguish among various shades of a single color.

Real-life example:

Mirrors help us see our Image.

We use Mirrors at beauty salons, on vehicle headlights, torchlights, streetlamps,