Reflection of Light

Confused about reflection of light??????

    WATCH THIS!!!!!!

Refraction of light

Refraction of light!!!!!!

Formation of Image by a Concave Mirror and Lens

Formation of Image by a Concave Mirror

When the Object is Placed At Infinity

When an object is placed at infinity, the rays coming from it are parallel to each other. Let us consider two rays, one striking the mirror at its pole and the other passing through the centre of curvature. The ray which is incident at the pole gets reflected according to the law of reflection and the second ray which passes through the centre of curvature of the mirror retraces its path. These rays after reflection form an image at the focus. The image formed is real, inverted and diminished.

The image is

• at F
• Real
• Inverted
• Diminished

When the Object is Placed Beyond C

The two rays which are considered to obtain the image are:

• a ray passing through the centre of curvature
• a ray parallel to the principal axis.

The ray passing through the centre of curvature retraces its path and the ray which is parallel to the principal axis passes through the focus after reflection. These rays after reflection meet at a point between C and F. The image is inverted, real and diminishedThe image is

• Between C and F
• Real
• Inverted
• Diminished

When the Object is Placed at the Center of Curvature

Here we consider the two rays, one parallel to the principal axis and the other passing through the focus. The ray of light which is parallel to the principal axis passes through the focus after reflection. The other ray passing through the focus after reflection emerges parallel to the axis. After reflection these rays meet at the centre of curvature to form an inverted image, which is real and of the same size as the object.

The image is

• At C
• Real
• Inverted
• Same size as object

When the Object is Between C and F

Here we consider a ray of light which is parallel to the principal axis and another ray passing through the focus. The ray which is parallel to the principal axis passes through the principal focus and the ray which passes through the focus after reflection emerges parallel to the principal axis. The reflected rays meet at a point beyond C and the image is real, inverted and magnified.
The image is

• Beyond C
• Real
• Inverted
• Magnified

When the Object is at the Focus

Here, we consider a ray of light which is parallel to the principal axis and another ray passing through the centre of curvature. The ray which is parallel to the principal axis passes through the focus and the ray which passes through the centre of curvature retraces its path. The reflected rays are parallel to each other, and would meet only at infinity i.e., the image is formed at infinity and it is a real, inverted and enlarged.

• The image is at infinity
• Real
• Inverted
• Magnified

When the Object is Between the Pole and the Focus

Here we consider a ray of light which is parallel to the principal axis and another ray which is passing through the centre of curvature. The ray which is passing through the centre of curvature retraces its path and the other ray which is parallel to the principal axis after reflection passes through the focus. These rays appear to meet behind the mirror when the reflected rays are extended backwards. The image is virtual, erect and magnified.

Formation of Image by a Concave Lens

When the Object is at Infinity: 

The image is -

• Formed at F₁

• Erect

• Virtual

• Diminished

When the Object is Placed between O and F:

The image is -

• Formed between O and F₁

• Erect

• Virtual

• Diminished

When the Object is Placed at any Position between O and Infinity:

The image is -

• Formed between O and F₁

• Erect

• Virtual

• Diminished

Formation of Image in a Convex Mirror and Lens

Formation of Image in a Convex Mirror

When the Object is between Infinity and the Pole

The image is

• Formed between the pole and the focus

• Erect

• Diminished

• Virtual

When the Object is at Infinity

The image is

• Formed at the focus

• Extremely diminished

• Virtual

• Erect

Formation of Image by a Convex Lens

1. When the Object is Placed between F₁ and O:

Formation of Image by a Convex Lens
The image is -

• Formed on the same side of the lens

• Virtual

• Erect

• Magnified

2. When the Object is Placed between the Optical Center (O) and first Focus (F₁)

Here we consider two rays starting from the top of the object placed at F₁ and optical center. The ray parallel to the principal axis after refraction passes through the focus (F₂). The ray passing through the optical center goes through the lens undeviated. These refracted rays appear to meet only when produced backwards. Thus, when an object is placed between F₁ and O of a convex lens, a virtual, erect and magnified image of the object is formed on the same side of the lens as the object.

3. When the Object is Placed at 2F₁

The image is -

• Formed at 2F₂

• Real

• Inverted

• Same size as the object

Here one of the rays starting from the top of the object placed at 2F₁ passes through the optic center without any deviation and the other ray which is parallel to the principal axis after refraction passes through the focus. These two refracted rays meet at 2F₂. Thus, when an object is placed at 2F₁ of a convex lens, inverted and real image of the same size as the object is formed at 2F₂ on the other side of the lens.

4. When the Object is Placed between F₁ and F₂

The image is

• Formed beyond 2F₂

• Real

• Inverted

• Magnified

Let us consider two rays coming from the object. The ray which is parallel to the principal axis after refraction passes through the lens and passes through F₂ on the other side of the lens. The ray passing through the optic center comes out of the lens without any deviation. The two refracted rays intersect each other at a point beyond 2F₂. So, when an object is placed between F₁ and 2F₁ of a convex lens the image is formed beyond 2F₂.

5. When the Object is Placed at F₁

The image is -

• Formed at infinity

• real

• Inverted

• Magnified

Here again we consider two rays coming from the top of the object. One of the rays which is parallel to the principal axis after refraction passes through F₂ and the other ray which passes through the optical center comes out without any deviation. These two refracted rays are parallel to each other and parallel rays meet only at infinity. Thus, when an object is placed at F₁ of a convex lens, the image is formed at infinity and it is inverted, real and magnified.

6. When the Object is Placed beyond 2F₁

The image is -

• Formed between F₂ and 2F₂

• Real

• Inverted

• Diminished

The ray parallel to the principal axis after refraction passes through F₂ and the ray which passes through the optical center comes out without any deviation. The refracted rays intersect at a point between F₂ and 2F₂. The image is inverted, real and diminished.

7. When the Object is Placed at Infinity

The image is -

• Formed at F₂

• Inverted

• Real

• Highly diminished

When the object is at infinity, the rays coming from it are parallel to each other. Let one of the parallel rays pass through the focus F₁ and the other ray pass through the optical center. The ray which passes through F₁ becomes parallel to the principal axis after refraction and the ray which passes through the optical center does not suffer any deviation.

human eye