For yellow light, r=90$^{\circ}$, when $i=c$ since $i$ is kept $c$ should be smaller for total reflection

the real image is formed when two or more reflected or refracted rays actually meet at a point.

Except mirror all other causes irregular reflection

A highly polished surface acts like a reflecting surface which allows regular reflection to take place.

Regular reflection is produced when light falls on highly polished surface.

When parallel rays of light are incident on a highly polished plane surface, after reflection, the rays emerge parallel as well. This type of reflection is called regular reflection.

Regular reflection occurs from smooth surfaces and images are formed in this type of reflection.

Irregular reflection occurs when parallel rays of light are incident on an irregular or rough surface and after reflection emerge in different directions. This type of reflection occurs due to irregularity of the reflecting surface.

We see an object when light comes from the same. As moon is not a natural source of light, it reflects light rays from the Sun and we are able to see it.

When all the parallel rays reflected from a plane surface are parallel, the reflection is known as regular reflection .

Images are formed by regular reflection. Diffused or irregular reflections can not form images.

Diffused reflection is not due to failure of laws of reflection but it is due to irregularities in the reflecting surface, like that of cardboard.

We can"t see our image on a cardboard because cardboard"s surface is rough and the reflection occurring on uneven surface is irregular reflection. So, the rays, after reflection, move to different directions. Images are not formed due to irregular reflections.

There are two kinds of reflection
i)regular reflection
ii)irregular reflection

Regular reflection takes place when a light beam is incident on a smooth surface which is highly polished.

A perfect smooth and shiny surface will reflect most of the light falling on them.

The speed at which the image of the car appears to approach the driver will be $(2 \times 8) m s^{-1} = 16 m s^{-1}$ because rear view mirror is a plane mirror.

All type of reflection obeys laws of reflection.

In regular reflection, parallel rays of light, after reflection, emerge as parallel.

Irregular reflection always obeys laws of reflection.

In a diffused or irregular reflection, parallel rays of light, after striking a rough and curved surface, get reflected irregularly.

A surface behaves as a smooth surface as long as the surface irregularities are small compared with the wavelength of the incident light.

When a light ray is reflected in many directions from a surface like a rock, it is called as diffused (or Irregular) reflection.

The reflection taking place from the walls of a building is called diffused reflection.
In diffused reflection, the reflected rays are not parallel to each other. This kind of reflection occurs from a coarse surface. Walls of a building being coarse surfaces, give rise to diffused reflections.