Question

1) state the law of refraction of light with two examples for refraction of light in daily life
2) a convex lens of focal length is 10 cm calculate its power?

Answer 1

1)

Laws of refraction of light

1) The incident ray , refracted ray and the normal to the interface of two media at the point of incidence , all lie in the same plane.

2) The ratio of the sine of angle of incidence to the sine of angle of refraction is a constant , for a given color of light and given pair of media.

Examples of refraction in daily life

1) Bending of light  when entering in the glass filled with water.

2) rainbow formation

3) a stick held obliquely which is partially immersed in water appear bent at the surface of water.

2)

focal length of convex lens = 10 cm

power = 1 / focal length

(where focal length is in metres )

changing the unit of focal length

f of convex lens = 10 cm = 10 / 100 m = 0.1 m

so,

Power = 1 / 0.1

power = +10 D

Answer 2

Answer:

Explanation:

1.  incident ray, refracted ray, and normal line lie on a same plane.                       snell's law- the ratio of the sine of the angle of incidence(i) to the sine of the angle of refraction(r) is equal to a constant(μ) where μ is called refractive index of second medium with respect to first medium.          i.e, μ=μ2/μ1                                                                                                            μ= Sin i/ Sin r                                                                  examples of refraction: a) the sun is visible before actual sunrise and after actual sunset due to atmospheric refraction.                                              b) bending of sunlight in raindrops                                   c) brilliance of diamond is due to total internal refraction
2. power = reciprocal of focal length                                                                so power = 1/10= 0.1 cm^-1 = 10 m^-1 = 10D                          D for diopter(unit of power)