i) Silver metal is the best reflector of light.
ii) A thin layer of silver is deposited on the side of materials like plane glass sheet to make mirrors.

(i) Incident ray (ii) Reflected ray

i) The incident ray, the reflected ray and the normal at the point of intersection all lie in the same plane.
ii) The ratio of the sine of the angle of incidence (i) to the sine of the angle of refraction (r) is equal to the refractive index of the medium, which is a constant.
\(\frac { \sin\ i }{ \sin\ r } \)= μ

Refractive index of the medium is the ratio of the speed of light in the air to the speed of light in that particular medium.
μ = \(\frac { Speed\ of\ light\ in\ air\ (c) }{ Speed\ of\ light\ in\ the\ medium\ (v) } \)

i. Provide a wider field of view as they are curved outwards.
ii. Used in vehicles as rearview mirrors.
iii. Used in hallways of various buildings like hospital, hotels, schools, and stores.
iv. Mounted on a wall or ceiling where there are sharp turns.
v. Used on roads where there are sharp curves and turns.

i) Splitting of white light into its seven constituent colours on passing through a transparent medium is known as dispersion of light.
ii) Dispersion occurs because light of different colours present in white light have different wavelength and they travel at different speeds in a medium.
iii) The refraction of a light ray in a medium depends on its speed.
iv) As each coloured lights has a different speed, the constituent coloured lights are refracted at different extents inside the prism.
v) Refraction of a light ray is inversely proportional to its wavelength.
vi) Thus, the red coloured light which has a large wavelength is deviated less while the violet coloured light which has a short wavelength is deviated more.
vii) Formation of rainbow is an example of dispersion of white light.

_wμ_g = \(\frac { Refractive\ index\ of\ glass }{ Refractive\ index\ of\ water } \)
\(=\frac { \frac { 3 }{ 2 } }{ \frac { 4 }{ 3 } } =\frac { 9 }{ 8 } \)=1.125

Angle of inclination = 90°
Number of images for=\(\frac { { 360 }^{ 0 } }{ \theta } -1=\frac { { 360 }^{ 0 } }{ { 90 }^{ 0 } }\)-1=4-1=3

Radius of curvature (R) = 2 × focal length
= 2 × 7 = 14 cm

Object should be placed between focus and pole of the mirror.

3 x 10⁸ ms^-1